View allAll Photos Tagged Adamantine
Faceted diamonds - "Cumulus" brooch, out of focus to highlight refracted colors. (public display, Field Museum of Natural History, Chicago, Illinois, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Cassiterite ("wood tin") from Bolivia. (Deborah Roman collection)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The oxide minerals all contain one or more oxide anions (O-2). The oxide minerals include species that are hydroxy-oxides. The hydroxide minerals (those with one or more OH-) are usually considered together with the oxides. Many sulfide minerals are not stable in Earth-surface conditions. In the presence of oxygen and moisture, sulfide minerals tend to tarnish or alter to oxides and hydroxy-oxides. All except the most inert elements (such as the platinum-group elements and gold and noble gases) readily form oxides. Gold oxide forms only under special conditions.
Cassiterite is tin oxide - SnO2. It has a nonmetallic luster that is adamantine (diamond-like) or greasy or submetallic. It has a hardness of 6 to 7 on the Mohs Hardness Scale and has a moderately high specific gravity (= 7). Common colors are reddish and brownish and black. Cassiterite crystallizes in the tetragonal system and usually forms small, granular crystals. Some crystals are elbow-shaped. Crystal faces are often striated.
Cassiterite is one of the last minerals to crystallize in pegmatitic granites, so it is found associated with quartz and in some hydrothermal veins peripheral to igneous intrusions. Because of its specific gravity and relative stability, cassiterite also occurs in placer deposits, along with other heavy minerals such as gold, magnetite, ilmenite, garnet, and rutile.
"Wood tin" is concretionary cassiterite - the mineral grows in globular masses by precipitation from water (the above photo shows a large example). This happens because tin is slightly soluble - it occurs as Sn+2 in streams.
Cassiterite is the # 1 ore mineral for tin. America has very little cassiterite, but it has been reported from North Carolina and in the Black Hills in non-minable quantities. The Andes Mountains of South America have abundant cassiterite deposits - Bolivia and Peru have been top producers.
In the Bronze Age, tin was needed to make bronze. There are no good supplies of tin minerals around the Mediterranean, apart from some cassiterite deposits in Spain. However, ancient peoples likely did not know about those. It is suspected that ancient cultures such as the Phoenicians made use of a large supply of cassiterite in Cornwall, England. The earliest forms of bronze are actually copper-arsenic alloys. Copper-tin alloy - "true bronze" - has a much lower melting point than just copper, such that bronze is more easily worked and cast.
Important cassiterite-bearing areas include the Andes Mountains, Malaysia, Tasmania, Alaska, Nigeria, and China.
Locality: unrecorded/undisclosed site in La Paz Department, western Bolivia, western South America
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Photo gallery of cassiterite:
Sphalerite-pyrite from the Miocene of Peru.
Black = sphalerite (ZnS - zinc sulfide)
Brassy-gold = pyrite (FeS2 - iron sulfide)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
The crystalline sphalerite-pyrite plate shown above is from a mine near Cerro de Pasco in the Huaron Mining District in Peru. It is part of a widespread belt of Miocene-aged mineralization in the Andes Mountains. Mineralization in the Cerro de Pasco area occurred during the early Middle Miocene (~14.5 Ma) (see Noble & McKee, 1999).
Locality: Alimon Mine, southern Huaron Mining District, near the town of Cerro de Pasco, western Pasco Department, west-central Peru
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Reference cited:
Noble, D.C. & E.H. McKee. 1999. The Miocene Metallogenic Belt of central and northern Peru. in: Geology and ore deposits of the Central Andes. Society of Economic Geologists Special Publication 7: 155-193.
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Photo gallery of sphalerite:
The T.A.N.Z., or Temerarious Adamantine Navigator of (hostile) Zones is designed for warfare. It carries supplies, ammo, and troops through dangerous environments. Machine guns are mounted on the front and on the roofline, and a rotating high-caliber cannon / grenade launcher is ideally located on the roof.
Fluorescing diamonds from Russia (probably Siberia). (crystals are ~0.7 to 0.9 millimeters in size)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are about 5600 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known. Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
The Russian diamonds shown above are clear/colorless under white light. This photo was taken under ultraviolet (UV) light - "black light", which makes the diamonds fluoresce various shades of blues and magentas and other colors.
Why do some minerals fluoresce under UV light? When short-wavelength UV radiation, long-wavelength UV radiation, or x-rays bombard atoms, electron excitation occurs. But the electrons do not remain in an energetically excited state. They quickly give off energy and resume their normal energy levels. If the electron energy release is in the visible spectrum of light, a mineral glows, or fluoresces.
Yellow diamonds from Zaire ("D.R. Congo"). (crystals are ~1 to 1.5 millimeters in size)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5400 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Sphalerite & fluorite from Mexico. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
Near-black = sphalerite
Greenish = fluorite (CaF2 - calcium fluoride)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
Locality: Naica, Chihuahua, Mexico
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Photo gallery of sphalerite:
Sphalerite from Tennessee, USA. (~8.5 centimeters across at its widest)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
The crystalline sphalerite specimen shown above is from the well-known Central Tennessee Zinc District (a.k.a. Central Tennessee Ba-F-Pb-Zn District). In this mining district, sphalerite mineralization is hosted in shallow marine dolostones of the upper Knox Group (Lower Ordovician) - probably from dissolution collapse brecciated and karstified dolomitized limestones of the Mascot Dolomite. The Central Tennessee Zinc District is a Mississippi Valley-type deposit in the Nashville Dome. It formed by mineralization from heavy metal-rich basinal brines that migrated from the adjacent Illinois Basin or Appalachian Basin. Published research indicates that mineralization occurred during the Late Paleozoic (Mississippian to Permian) and was associated with the Allegheny Orogeny, a tectonic collision event between Africa and North America. Main stage calcite in the Central Tennessee Mining District dates to 260±42 Ma (= Late Permian).
Locality: attributed to a mine near the town of Carthage, Smith County, north-central Tennessee, USA
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Photo gallery of sphalerite:
Faceted diamonds - "Cumulus" brooch with 8 carat diamond at top. (public display, Field Museum of Natural History, Chicago, Illinois, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Large diamond crystal (28.45 carats) from Zaire ("D.R. Congo"), collected circa 1930s.
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Faceted diamond, illuminated by one light source and showing the famous "fire" of gem-quality diamond. (4.75 mm across at its widest)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Phosphorescing diamonds from an undisclosed locality. (each crystal is on the order of 0.5 millimeters in size)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are about 5600 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known. Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
The diamonds shown above are clear/colorless under white light and glow blue, magenta, green, and other colors under black light (ultraviolet light; UV). This photo was taken just after a UV light was turned off - no external light source is present. The soft glowing green and blue colors are phosphorescence.
Sphalerite-barite in breccia from Colorado, USA. (public display, Geology Department, Wittenberg University, Springfield, Ohio, USA)
Gray = host rock
Light-colored material = barite
Dark-colored material = sphalerite
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
In the rock sample shown above, dark-colored sphalerite and light-colored barite are filling fractures in the brecciated host rock. It comes from an old silver mine near Leadville, Colorado.
Locality: Day Mine (also known as the Old Sherman Mine), upper Iowa Gulch, Mt. Sherman, east of the town of Leadville, Leadville Mining District, Lake County, west-central Colorado, USA
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Photo gallery of sphalerite:
Sphalerite & barite from Tennessee, USA. (CMC RM 1140, Cincinnati Museum Center's rock & mineral collection, Cincinnati Museum of Natural History & Science, Cincinnati, Ohio, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
Locality: Cumberland Mine, Smith County, Tennessee, USA
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Photo gallery of sphalerite:
Cassiterite ("wood tin") from Britain. (Deborah Roman collection)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The oxide minerals all contain one or more oxide anions (O-2). The oxide minerals include species that are hydroxy-oxides. The hydroxide minerals (those with one or more OH-) are usually considered together with the oxides. Many sulfide minerals are not stable in Earth-surface conditions. In the presence of oxygen and moisture, sulfide minerals tend to tarnish or alter to oxides and hydroxy-oxides. All except the most inert elements (such as the platinum-group elements and gold and noble gases) readily form oxides. Gold oxide forms only under special conditions.
Cassiterite is tin oxide - SnO2. It has a nonmetallic luster that is adamantine (diamond-like) or greasy or submetallic. It has a hardness of 6 to 7 on the Mohs Hardness Scale and has a moderately high specific gravity (= 7). Common colors are reddish and brownish and black. Cassiterite crystallizes in the tetragonal system and usually forms small, granular crystals. Some crystals are elbow-shaped. Crystal faces are often striated.
Cassiterite is one of the last minerals to crystallize in pegmatitic granites, so it is found associated with quartz and in some hydrothermal veins peripheral to igneous intrusions. Because of its specific gravity and relative stability, cassiterite also occurs in placer deposits, along with other heavy minerals such as gold, magnetite, ilmenite, garnet, and rutile.
"Wood tin" is concretionary cassiterite - the mineral grows in globular masses by precipitation from water (see the above photo for an excellent example). This happens because tin is slightly soluble - it occurs as Sn+2 in streams.
Cassiterite is the # 1 ore mineral for tin. America has very little cassiterite, but it has been reported from North Carolina and in the Black Hills in non-minable quantities. The Andes Mountains of South America have abundant cassiterite deposits - Bolivia and Peru have been top producers.
In the Bronze Age, tin was needed to make bronze. There are no good supplies of tin minerals around the Mediterranean, apart from some cassiterite deposits in Spain. However, ancient peoples likely did not know about those. It is suspected that ancient cultures such as the Phoenicians made use of a large supply of cassiterite in Cornwall, England. The earliest forms of bronze are actually copper-arsenic alloys. Copper-tin alloy - "true bronze" - has a much lower melting point than just copper, such that bronze is more easily worked and cast.
Important cassiterite-bearing areas include the Andes Mountains, Malaysia, Tasmania, Alaska, Nigeria, and China.
Locality: Polberro Mines, near the town of St. Agnes, St. Agnes Mining District, near the northern shore of the Cornwall Peninsula, England, far-southwestern Britain
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Photo gallery of cassiterite:
Diamond from Sierra Leone, West Africa. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Zinc ore from Missouri, USA. (public display, Geology Department, Wittenberg University, Springfield, Ohio, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
The rock shown here is zinc ore consisting of sphalerite replacing dolostone (Bonneterre Dolomite, Upper Cambrian). It comes from a now-closed zinc mine in Missouri. Relict silty layers are still evident, despite the mineralization.
This specimen is from a Mississippi Valley-type deposit. Commonly abbreviated "MVT", Mississippi Valley-type deposits are named for a series of mineral deposits that occur in non-deformed platform sedimentary rocks along the Upper Mississippi River Valley, USA. Many specific minerals occur in MVT deposits, but are dominated by galena, sphalerite, barite, and fluorite. These minerals occur in caves and karst, paleokarst structures, in collapse fabrics, in pull-apart structures, etc. MVT deposits in America are mined as important, large sources of lead ore and zinc ore. The classic areas for MVT deposits are southern Illinois, the tristate area of Oklahoma-Missouri-Kansas, northern Kentucky, southwestern Wisconsin, and southeastern Missouri. The minerals are hydrothermal in origin and were precipitated from basinal brines that were flushed out to the edges of large sedimentary basins (e.g., the Illinois Basin and the Black Warrior Basin). In basin edge areas, the brines came into contact with Mississippian-aged carbonate rocks (limestone and dolostone), which caused mineralization. The brines were 15% to 25% salinity with temperatures of 50 to 200 degrees Celsius (commonly 100 to 150 degrees C). MVT mineralization usually occurs in limestone and dolostone but can also be hosted in shales, siltstones, sandstones, and conglomerates. Gangue minerals include pyrite, marcasite, calcite, aragonite, dolomite, siderite, and quartz. Up to 40 or 50 pulses of brine fluids are recorded in banding of mineral suites in MVT deposits (for example, sphalerite coatings in veins have a stratigraphy - each layer represents a pulse event). Each pulse of water was probably expelled rapidly - overpressurization and friction likely caused the water to heat up. Some bitumen (crystallized organic matter) can occur, which is an indication of the basinal origin of the brines. The presence of asphalt-bitumen indicates some hydrocarbon migration occurred. Some petroleum inclusions are found within fluorite crystals and petroleum scum occurs on fluorite crystals. MVT deposits are associated with oil fields and the temperature of mineral precipitation matches the petroleum window. The brines may simply have accompanied hydrocarbon fluids as they migrated updip.
The high temperatures of these basin periphery deposits wasn't necessarily influenced by igneous hydrothermal activity. Hot fluids can occur in basins that are deep enough for the geothermal gradient to be ~100 to 150 degrees Celsius. If a permeable conduit horizon is present in a succession of interbedded siliciclastic sedimentary rocks, migration of hot, deep basinal brines may be quick enough to get MVT deposit conditions at basin margins.
MVT deposits occur in the Upper Mississippi Valley of America as well as in northern Africa, Scandinavia, northwestern Canada, at scattered sites in Europe, and at some sites in the American Cordillera. Some of these occurrences are in deformed host rocks. MVT deposits have little to no precious metals - maybe a little copper (Cu). Mineralization is usually associated with limestone or dolostone in fracture fillings and vugs. Little host rock alteration has occurred - usually only dolomitization of limestones.
The age of the host rocks in the Mississippi Valley area varies - it ranges from Cambrian to Mississippian. Dating of mineralization has been difficult, but published ages indicate a near-latest Paleozoic to Mesozoic timing.
MVT deposits in the Upper Mississippi River area are often divided into three subtypes based on the dominant mineral: 1) lead-rich (galena dominated); 2) zinc-rich (sphalerite dominated); and 3) fluorite-rich.
Locality: Magmont Mine, New Lead Belt, south-southwest of the town of Bixby, northwestern Iron County, southeastern Missouri, USA
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Photo gallery of sphalerite:
Yarr! Testing out new darker style.
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Helena is a SOOM MD Topaz
Face-up by Adamantine
Photography © Primadonna dolls
Diamond from Sierra Leone, West Africa. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Fluorescing diamonds from Russia (probably Siberia). (crystals are ~0.7 to 0.9 millimeters in size)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are about 5600 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known. Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
The Russian diamonds shown above are clear/colorless under white light. This photo was taken under ultraviolet (UV) light - "black light", which makes the diamonds fluoresce various shades of blues and magentas and other colors.
Why do some minerals fluoresce under UV light? When short-wavelength UV radiation, long-wavelength UV radiation, or x-rays bombard atoms, electron excitation occurs. But the electrons do not remain in an energetically excited state. They quickly give off energy and resume their normal energy levels. If the electron energy release is in the visible spectrum of light, a mineral glows, or fluoresces.
Faceted diamonds - "Cumulus" brooch with 8 carat diamond at top. (public display, Field Museum of Natural History, Chicago, Illinois, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Sphalerite from Tennessee, USA. (field of view ~6.0 centimeters across)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
The crystalline sphalerite specimen shown above is from the well-known Central Tennessee Zinc District (a.k.a. Central Tennessee Ba-F-Pb-Zn District). In this mining district, sphalerite mineralization is hosted in shallow marine dolostones of the upper Knox Group (Lower Ordovician) - probably from dissolution collapse brecciated and karstified dolomitized limestones of the Mascot Dolomite. The Central Tennessee Zinc District is a Mississippi Valley-type deposit in the Nashville Dome. It formed by mineralization from heavy metal-rich basinal brines that migrated from the adjacent Illinois Basin or Appalachian Basin. Published research indicates that mineralization occurred during the Late Paleozoic (Mississippian to Permian) and was associated with the Allegheny Orogeny, a tectonic collision event between Africa and North America. Main stage calcite in the Central Tennessee Mining District dates to 260±42 Ma (= Late Permian).
Locality: attributed to a mine near the town of Carthage, Smith County, north-central Tennessee, USA
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Photo gallery of sphalerite:
After some time, Polydectes fell in love with Danaë and desired to remove Perseus from the island. He therefore hatched a plot to send him away in disgrace.
Polydectes announced a large banquet where each guest was expected to bring a gift.[note 2] Polydectes requested that the guests bring horses, under the pretense that he was collecting contributions for the hand of Hippodamia, "tamer of horses". The fisherman's protegé had no horse to give, so asked Polydectes to name the gift, for he would not refuse it. Polydectes held Perseus to his rash promise, demanding the head of the only mortal Gorgon,[6] Medusa, whose very expression turned people to stone. Ovid's anecdotal embroidery of Medusa's mortality tells that she had once been a woman, vain of her beautiful hair, who lay with Poseidon in the Temple of Athena.[7] In punishment for the desecration of her temple, Athena changed Medusa's hair into hideous snakes "that she may alarm her surprised foes with terror".[8]
Athena instructed Perseus to find the Hesperides, who were entrusted with weapons needed to defeat the Gorgon. Following Athena's guidance,[9] Perseus sought out the Graeae, sisters of the Gorgons, to demand the whereabouts of the Hesperides, the nymphs tending Hera's orchard. The Graeae were three perpetually old women, who had to share one eye and one tooth between them. As the women passed the eye from one to the other, Perseus snatched it from them, holding it ransom in return for the location of the nymphs.[10] When the sisters led him to the Hesperides, he returned what he had taken.
From the Hesperides, he received various treasures: a knapsack kibisis to safely contain Medusa's head, winged sandals to fly, Hades' helm of invisibility to hide. Hermes loaned Perseus an adamantine sword, while Athena gave him a polished shield. Perseus then proceeded to the Gorgons' cave.
In the cave he came upon the sleeping Stheno, Euryale and Medusa. By viewing Medusa's reflection in his polished shield, he safely approached and cut off her head. From her neck sprang Pegasus ("he who sprang") and Chrysaor ("bow of gold"), the result of Poseidon and Medusa's meeting. The other two Gorgons pursued Perseus,[11] but under his helmet of invisibility he escaped.
Antonio Canova (1 November 1757 – 13 October 1822) was a Venetian sculptor who became famous for his marble sculptures that delicately rendered nude flesh. The epitome of the neoclassical style, his work marked a return to classical refinement after the theatrical excesses of Baroque sculpture.
Among Canova's heroic compositions, his Perseus with the Head of Medusa (photo, right) appeared soon after his return from Germany. The moment of representation is when the hero, flushed with conquest, displays the head of the "snaky Gorgon", whilst the right hand grasps a sword of singular device. By a public decree, this fine work was placed in one of the stanze of the Vatican hitherto reserved for the most precious works of antiquity.
Diamond from Sierra Leone, West Africa. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Vanadinite from Arizona, USA. (~12.2 centimeters across at its widest)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5500 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Vanadinite is a beautiful, uncommon, reddish-colored lead chlorovanadate mineral (Pb5(VO4)3Cl). Vanadinite has hexagonal crystals, a hardness of 3, and a nonmetallic luster described as adamantine or resinous.
The example seen here consists of numerous small vanadinite crystals coating matrix. It comes from Arizona's Apache Mine, which has an abundance of vanadinite crystals. The site was mined from the late 1920s to the 1950s. The vanadium obtained from vanadinite crystals was principally used in steel making.
Locality: Apache Mine, north-northwest of the town of Globe, Globe Hills Mining District, southern Gila County, Arizona, USA
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Photo gallery of vanadinite:
www.mindat.org/gallery.php?min=4139
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Site description, history, and geology:
Cinnabar from California, USA.
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Cinnabar is a mercury sulfide mineral (HgS). It is one of the few sulfide minerals that lacks a metallic luster (other examples are orpiment & realgar). In its crystalline form, cinnabar has an intense adamantine luster. Massive, fine-grained specimens generally have an earthy luster. Cinnabar has a reddish color reddish streak, 3 different cleavage planes, is quite soft (H = 2 to 2.5), and is heavy for its size (high specific gravity).
Cinnabar principally occurs in some young volcanic rocks and hydrothermal spring deposits. It's a fairly volatile chemical - much of it passes out from volcanic vents into the atmosphere as a gas.
Cinnabar is the most important ore mineral for the element mercury and was long used as a red pigment.
Locality: New Almaden, New Almaden Mining District, Santa Cruz Mountains, Santa Clara County, western central California, USA
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Photo gallery of cinnabar:
I needed to sell her but she was saved by the bell when Adamantine gave her new ginger look. :)
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Rosémary is a SOOM MD Cuprit
Face-up by Adamantine
Photography © Primadonna dolls
Faceted diamond, illuminated by one light source and showing the famous "fire" of gem-quality diamond. (4.75 mm across at its widest)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Diamonds from Africa. (crystal at lower left is ~2.5 mm across)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
The rough African diamonds shown above display the two common crystal forms - cubes and octahedrons (= double pyramids). The yellowish-gray specimens are cubes to slightly mis-shapen cubes. The two clearish specimens are octahedral diamond crystals with inclusions.
Faceted diamonds - "Cumulus" brooch with 8 carat diamond at top. (public display, Field Museum of Natural History, Chicago, Illinois, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Sphalerite on galena from Bulgaria. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
Near-black = sphalerite
Silvery-gray = galena (PbS - lead sulfide)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
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Photo gallery of sphalerite:
Sphalerite on galena from Bulgaria. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)
Near-black = sphalerite
Silvery-gray = galena (PbS - lead sulfide)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
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Photo gallery of sphalerite:
Faceted diamonds - "Cumulus" brooch with 8 carat diamond at top. (public display, Field Museum of Natural History, Chicago, Illinois, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Flint contains many small diamond like structures,
“I could perceive the whole surface of that cavity to be all beset with a multitude of little Crystaline or Adamantine bodies, so curiously shap'd, that it afforded a not unpleasing object”
Also in this plate there is a rather more peculiar image. Hooke was intrigued as to what the “gravel in urine” was so. This is certainly one of the stranger things Hooke decided to take a look at with his microscope….
University of Glasgow Library
Special Collections
Robert Hooke
Micrographia
Sp Coll Hunterian M.3.1
Sphalerite from Oklahoma, USA. (3.7 centimeters across at its widest)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 6100 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Sphalerite is a somewhat common zinc sulfide mineral (ZnS). It has a metallic to submetallic to resinous to adamantine luster. Many metals can substitute for the zinc, such as iron, cadmium, and manganese. Sphalerite almost always has some iron in it, so a better chemical formula would be (Zn,Fe)S. Sphalerite has a wide color range, depending principally on iron content. Pure to almost pure sphalerite is whitish to greenish. With increasing iron content, sphalerite becomes yellowish to brownish to blackish. One variety of sphalerite has a strikingly intense dark red color (ruby sphalerite). Its streak color also varies with iron content from whitish to pale yellowish to brownish. Sphalerite is also distinctive in being moderately heavy for its size and having six different planes of cleavage.
Sphalerite is the most important zinc ore mineral. Zinc produced from sphalerite is used for many purposes, including mixing with copper to produce brass, rust protection of iron & steel, and for making modern American pennies (although the cost of making each zinc penny is more than 1¢).
Locality: Tri-State Mining District, Oklahoma, USA
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Photo gallery of sphalerite:
Cinnabar from Spain. (CMNH 18757, Cleveland Museum of Natural History, Cleveland, Ohio, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The sulfide minerals contain one or more sulfide anions (S-2). The sulfides are usually considered together with the arsenide minerals, the sulfarsenide minerals, and the telluride minerals. Many sulfides are economically significant, as they occur commonly in ores. The metals that combine with S-2 are mainly Fe, Cu, Ni, Ag, etc. Most sulfides have a metallic luster, are moderately soft, and are noticeably heavy for their size. These minerals will not form in the presence of free oxygen. Under an oxygen-rich atmosphere, sulfide minerals tend to chemically weather to various oxide and hydroxide minerals.
Cinnabar is a mercury sulfide mineral (HgS). It is one of the few sulfide minerals that lacks a metallic luster (other examples are orpiment & realgar). In its crystalline form, cinnabar has an intense adamantine luster. Massive, fine-grained specimens generally have an earthy luster. Cinnabar has a reddish color reddish streak, 3 different cleavage planes, is quite soft (H = 2 to 2.5), and is heavy for its size (high specific gravity).
Cinnabar principally occurs in some young volcanic rocks and hydrothermal spring deposits. It's a fairly volatile chemical - much of it passes out from volcanic vents into the atmosphere as a gas.
Cinnabar is the most important ore mineral for the element mercury and was long used as a red pigment.
Locality: Almaden, Ciudad Real, south-central Spain
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Photo gallery of cinnabar:
Faceted diamonds - "Cumulus" brooch with 8 carat diamond at top. (public display, Field Museum of Natural History, Chicago, Illinois, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Diamonds from the Wyoming-Colorado border area, USA. (public display, Wyoming Geological Survey, Laramie, Wyoming, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5400 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known. Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
A decent number of kimberlite bodies have been identified in the Rocky Mountains along the Colorado-Wyoming border, forming the State Line Kimberlite Field. The field is traditionally considered to represent many kimberlite bodies emplaced at about the same time. Recent isotopic dating has indicated this is not the case.
Locality: undisclosed site accessible to Cominco American Incorporated
Faceted diamonds - "Cumulus" brooch with 8 carat diamond at top. (public display, Field Museum of Natural History, Chicago, Illinois, USA)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5200 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals.
To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.
The element carbon occurs principally in its native state as graphite (C) and diamond (C). Graphite is the common & far less valuable polymorph of carbon. A scarce polymorph of carbon is diamond. The physical properties of diamond and graphite couldn’t be more different, considering they have the same chemistry. Diamond has a nonmetallic, adamantine luster, typically occurs in cubic or octahedral (double-pyramid) crystals, or subspherical to irregularly-shaped masses, and is extremely hard (H≡10). Diamonds can be almost any color, but are typically clearish, grayish, or yellowish. Many diamonds are noticeably fluorescent under black light (ultraviolet light), but the color and intensity of fluorescence varies. Some diamonds are phosphorescent - under certain conditions, they glow for a short interval on their own.
Very rarely, diamond is a rock-forming mineral (see diamondite - www.flickr.com/photos/jsjgeology/14618393527).
Done in Ai, Finalized in Photoshop.
The Eclipse Requiem is the flagship of Xal’Zareth Nyrr’Kael — a world-razor built not merely to wage war, but to declare that hope is obsolete.
Forged in the orbital ship-cradles of Vyr’Kos, it combines ancient dreadnought engineering with forbidden energy cores recovered from stellar collapse. Its massive hull is plated in black adamantine, angular and brutalist in form, bristling with titanic artillery batteries, void cannons, and ion lances capable of silencing entire star fleets. Turrets rotate with silent precision; glowing violet apertures line its spine, each a war-mouth waiting to open.
The towering superstructure rises like a cathedral of annihilation — lined with signal masts, dreadspire towers, and execution decks. Its engines burn with eerie ultraviolet glow, bending starlight in their wake. Ornate glyphwork across its hull pulses faintly with the will of its queen, directing the ship like an extension of her consciousness.
It moves with sovereign patience — not fast, but unstoppable.
My tiny mori bunny waiting for her eyes. :)
EDIT
She's now in a new home. :)
--
Madeleine is a Tendres Chimères Fenouil (lait fraise)
Face-up by Adamantine
Clothes by Raouken, Princess doll
Photography © Lily
Vanadinite from Morocco.
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5500 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
Vanadinite is an uncommon, but beautiful, reddish-colored lead chlorovanadate (Pb5(VO4)3Cl). Vanadinite has hexagonal crystals, a hardness of 3, and a nonmetallic luster described as adamantine or resinous.
The highest quality vanadinite is from Morocco in northwestern Africa. Shown above is a spectacular cluster of Moroccan vanadinite crystals that have grown atop Jurassic dolostone.
Locality: A'hcif Mine (A'hcif Shaft), near the old mining village of Mibladen, ~15 km northeast of Midelt, eastern Khenifra Province, northern Morocco
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Photo gallery of vanadinite:
Cassiterite ("wood tin") from Bolivia. (Deborah Roman collection)
A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 5500 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.
The oxide minerals all contain one or more oxide anions (O-2). The oxide minerals include species that are hydroxy-oxides. The hydroxide minerals (those with one or more OH-) are usually considered together with the oxides. Many sulfide minerals are not stable in Earth-surface conditions. In the presence of oxygen and moisture, sulfide minerals tend to tarnish or alter to oxides and hydroxy-oxides. All except the most inert elements (such as the platinum-group elements and gold and noble gases) readily form oxides. Gold oxide forms only under special conditions.
Cassiterite is tin oxide - SnO2. It has a nonmetallic luster that is adamantine (diamond-like) or greasy or submetallic. It has a hardness of 6 to 7 on the Mohs Hardness Scale and has a moderately high specific gravity (= 7). Common colors are reddish and brownish and black. Cassiterite crystallizes in the tetragonal system and usually forms small, granular crystals. Some crystals are elbow-shaped. Crystal faces are often striated.
Cassiterite is one of the last minerals to crystallize in pegmatitic granites, so it is found associated with quartz and in some hydrothermal veins peripheral to igneous intrusions. Because of its specific gravity and relative stability, cassiterite also occurs in placer deposits, along with other heavy minerals such as gold, magnetite, ilmenite, garnet, and rutile.
"Wood tin" is concretionary cassiterite - the mineral grows in globular masses by precipitation from water (the above photo shows a large example). This happens because tin is slightly soluble - it occurs as Sn+2 in streams.
Cassiterite is the # 1 ore mineral for tin. America has very little cassiterite, but it has been reported from North Carolina and in the Black Hills in non-minable quantities. The Andes Mountains of South America have abundant cassiterite deposits - Bolivia and Peru have been top producers.
In the Bronze Age, tin was needed to make bronze. There are no good supplies of tin minerals around the Mediterranean, apart from some cassiterite deposits in Spain. However, ancient peoples likely did not know about those. It is suspected that ancient cultures such as the Phoenicians made use of a large supply of cassiterite in Cornwall, England. The earliest forms of bronze are actually copper-arsenic alloys. Copper-tin alloy - "true bronze" - has a much lower melting point than just copper, such that bronze is more easily worked and cast.
Important cassiterite-bearing areas include the Andes Mountains, Malaysia, Tasmania, Alaska, Nigeria, and China.
Locality: unrecorded/undisclosed site in La Paz Department, western Bolivia, western South America
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Photo gallery of cassiterite: