View allAll Photos Tagged Quartz
Fossil wood (quartz permineralized fossil wood) (2.2 cm across)
Plants are multicellular, photosynthetic eucaryotes. The oldest known land plant body fossils are Silurian in age. Fossil root traces of land plants are known back in the Ordovician. The Devonian was the key time interval during which land plants flourished and Earth experienced its first “greening” of the land. The earliest land plants were small and simple and probably remained close to bodies of water. By the Late Devonian, land plants had evolved large, tree-sized bodies and the first-ever forests appeared.
The fossil shown above is "petrified wood", which is a horrible term for what is technically called permineralization. Biogenic materials such as wood or bone have a fair amount of small-scale porosity. After burial, the porosity of wood or bone can get partially or completely filled up with minerals as groundwater or diagenetic fluids percolate through. The end result is a harder, denser material that retains the original three-dimensionality (or close to it). The wood or bone has become “petrified”. Well, no - it’s become permineralized. Not surprisingly, the most common permineralization mineral is quartz (SiO2). Sometimes, fossil wood and bone have been permineralized with radioactive minerals such as black uraninite (UO2) or yellowish carnotite (K2(UO2)2(VO4)2·3H2O). Recently, fossil bones permineralized with cinnabar have been identified (García-Alix et al., 2013, Lethaia 46: 1-6).
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First day of spring is dedicated to all the birds
Garden Village, Burnaby, British Columbia, Canada
Locality: Novo Horizonte, Bahia, Brazil
From the Collection of the Natural History Museum of Los Angeles
This is a little love struck Dragon, who's clearly swooning over someone (I think it's the Chinese Jade Dragon).
Amethyst (= purple quartz) from Brazil. (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 about 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.
The silicates are the most abundant and chemically complex group of minerals. All silicates have silica as the basis for their chemistry. "Silica" refers to SiO2 chemistry. The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4. Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon. The resulting formula for silica is thus SiO2, not SiO4.
The simplest & most abundant silicate mineral in the Earth's crust is quartz (SiO2). All other silicates have silica + impurities. Many silicates have a significant percentage of aluminum (the aluminosilicates).
Quartz (silicon dioxide/silica - SiO2) is the most common mineral in the Earth's crust. It is composed of the two most abundant elements in the crust - oxygen and silicon. It has a glassy, nonmetallic luster, is commonly clearish to whitish to grayish in color, has a white streak, is quite hard (H≡7), forms hexagonal crystals, has no cleavage, and has conchoidal fracture. Quartz can be any color: clear, white, gray, black, brown, pink, red, purple, blue, green, orange, etc.
Purple quartz is called amethyst. The coloring agent for amethyst is not agreed upon. Some workers say that it is due to Fe+4 impurity, some say the impurity is Fe+3, and others say it is Mn.
From museum signage:
"This geode was formed when amethyst crystals grew in an air bubble in basalt flows of Brazil.
Geodes are rounded, hollow bodies lined inside with crystals. The outer shell is typically formed of dense chalcedony, a type of quartz, and the inside is lined with crystals. The crystals lining this exceptionally large geode from brazil are amethyst, a semi-precious variety of quartz. Quartz crystals frequently form the inner lining of geodes, although crystals of calcite, dolomite, and other minerals occasionally are found.
Geodes are products of sedimentary environments, usually forming in limestones but also occurring in shales. They originate in a cavity in the rock, and grow by expansion. The crystals lining the inside of the geode form last, precipitated from ground water filling the cavity.
"
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Photo gallery of quartz and amethyst
www.mindat.org/gallery.php?min=3337
and
Locality:
Cavnic Mine, Cavnic, Romania
Class:
Crystal Group/Cluster
Size:
8 × 7 × 5 cm
Largest Crystal:
6.00cm
Description
very good group of perfect lustrous quartz crystals, largest is 6x4 cm
Locality: Piedra Parada (Las VIgas), Municipio de Tatatila, Vera Cruz, Mexico
Size: Primary crystal is 1.9 inches tall.
SC2-0336
58g
Rhodochrosite on Quartz. Rhodochrosite is manganese carbonate. Pachapaqui District. Bolognesi Province, Ancash Dept., Peru. (Collection of the Colorado School of Mines Geology Museum. Golden, Colo.)
Pseudofossils are inorganic objects, markings, or impressions that might be mistaken for fossils. Pseudofossils may be misleading, as some types of mineral deposits can mimic lifeforms by forming what appear to be highly detailed or organized structures. One common example is when manganese oxides crystallize with a characteristic treelike or dendritic pattern along a rock fracture. The formation of frost dendrites on a window is another common example of this crystal growth. Concretions are sometimes thought to be fossils, and occasionally one contains a fossil, but are generally not fossils themselves. Chert or flint nodules in limestone can often take forms that resemble fossils.
It's getting warm and in spring the Quartz Magpie starts their yearly mating ritual. The male birds suddenly light up and wait for the females to notice and brighten up their yellow belly as well. Quite some show...
Smoky Quartz with Dolomite and Chalcopyrite
Locality: Brad, Romania
Size: Front crystal is 2.5 inches tall, back crystal is 2.8 inches
SC2-0340
281gtall.
408 – Quartz (Mineral),
Luster: Non-Metallic Vitreous,
Hardness: 7,
Breakage: no cleavage, conchoidal fracture on crystal faces,
Description: Silicate mineral, very glassy and shiny, very hard mineral and can scratch most other common minerals, very common mineral on earth’s surface, commonly white/clear
These translucent, dipyramidal crystals are technically quartz pseudomorphs after beta quartz.
Loclaity: Dal'negorsk, Primorskiy Kray, Bor Pit, Russia
Size: Specimen is 2.1 inches wide.
SC2-0216
28g
Locality: Diamond Point, AZ
Notes: These growth hillocks are common on the rhombohedral faces of the quartz crystals from this area. The field of view is about 0.25 inches.
Amethyst (= purple quartz) from Brazil. (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 about 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.
The silicates are the most abundant and chemically complex group of minerals. All silicates have silica as the basis for their chemistry. "Silica" refers to SiO2 chemistry. The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4. Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon. The resulting formula for silica is thus SiO2, not SiO4.
The simplest & most abundant silicate mineral in the Earth's crust is quartz (SiO2). All other silicates have silica + impurities. Many silicates have a significant percentage of aluminum (the aluminosilicates).
Quartz (silicon dioxide/silica - SiO2) is the most common mineral in the Earth's crust. It is composed of the two most abundant elements in the crust - oxygen and silicon. It has a glassy, nonmetallic luster, is commonly clearish to whitish to grayish in color, has a white streak, is quite hard (H≡7), forms hexagonal crystals, has no cleavage, and has conchoidal fracture. Quartz can be any color: clear, white, gray, black, brown, pink, red, purple, blue, green, orange, etc.
Purple quartz is called amethyst. The coloring agent for amethyst is not agreed upon. Some workers say that it is due to Fe+4 impurity, some say the impurity is Fe+3, and others say it is Mn.
From museum signage:
"This geode was formed when amethyst crystals grew in an air bubble in basalt flows of Brazil.
Geodes are rounded, hollow bodies lined inside with crystals. The outer shell is typically formed of dense chalcedony, a type of quartz, and the inside is lined with crystals. The crystals lining this exceptionally large geode from brazil are amethyst, a semi-precious variety of quartz. Quartz crystals frequently form the inner lining of geodes, although crystals of calcite, dolomite, and other minerals occasionally are found.
Geodes are products of sedimentary environments, usually forming in limestones but also occurring in shales. They originate in a cavity in the rock, and grow by expansion. The crystals lining the inside of the geode form last, precipitated from ground water filling the cavity.
"
---------------
Photo gallery of quartz and amethyst
www.mindat.org/gallery.php?min=3337
and
Fossil wood (quartz permineralized fossil wood) (2.2 cm across)
Plants are multicellular, photosynthetic eucaryotes. The oldest known land plant body fossils are Silurian in age. Fossil root traces of land plants are known back in the Ordovician. The Devonian was the key time interval during which land plants flourished and Earth experienced its first “greening” of the land. The earliest land plants were small and simple and probably remained close to bodies of water. By the Late Devonian, land plants had evolved large, tree-sized bodies and the first-ever forests appeared.
The fossil shown above is "petrified wood", which is a horrible term for what is technically called permineralization. Biogenic materials such as wood or bone have a fair amount of small-scale porosity. After burial, the porosity of wood or bone can get partially or completely filled up with minerals as groundwater or diagenetic fluids percolate through. The end result is a harder, denser material that retains the original three-dimensionality (or close to it). The wood or bone has become “petrified”. Well, no - it’s become permineralized. Not surprisingly, the most common permineralization mineral is quartz (SiO2). Sometimes, fossil wood and bone have been permineralized with radioactive minerals such as black uraninite (UO2) or yellowish carnotite (K2(UO2)2(VO4)2·3H2O). Recently, fossil bones permineralized with cinnabar have been identified (García-Alix et al., 2013, Lethaia 46: 1-6).
Locality: Novo Horizonte, Bahia, Brazil
From the Collection of the Natural History Museum of Los Angeles
While clearing out the house, we unearthed a large box containing about 100 mineral stones that came from Elisa's old collection.
Naturally, I decided to photograph them.
General
Category: Silicate mineral
Formula (repeating unit): SiO2)
Strunz classification: 04.DA.05
Dana classification: 75.01.03.01
Crystal symmetry: Trigonal 32
Unit cell: a = 4.9133 Å, c = 5.4053 Å; Z=3
Identification
Color: Colorless through various colors to black
Crystal habit: 6-sided prism ending in 6-sided pyramid (typical), drusy, fine-grained to microcrystalline, massive
Crystal system: α-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal 622
Twinning: Common Dauphine law, Brazil law and Japan law
Cleavage: {0110} Indistinct
Fracture: Conchoidal
Tenacity: Brittle
Mohs scale hardness: 7 – lower in impure varieties (defining mineral)
Luster: Vitreous – waxy to dull when massive
Streak: White
Diaphaneity: Transparent to nearly opaque
Specific gravity: 2.65; variable 2.59–2.63 in impure varieties
Optical properties: Uniaxial (+)
Refractive index: nω = 1.543–1.545 nε = 1.552–1.554
Birefringence: +0.009 (B-G interval)
Pleochroism: None
Melting point: 1670 °C (β tridymite) 1713 °C (β cristobalite)
Solubility: Insoluble at STP; 1 ppmmass at 400 °C and 500 lb/in2 to 2600 ppmmass at 500 °C and 1500 lb/in2
Other characteristics: Piezoelectric, may be triboluminescent, chiral (hence optically active if not racemic)
Rose Quartz 1.41ct., 6.8x9.57x4.89mm. Custom Pendeloque
Most rose quartz is hazy and fuzzy looking. This material is from a surprising find in Madagascar a few years back. I thought it was unavailable, but I found some at Tucson this year -- of course, I came home with it. I am very pleased that the stone holds its color after cutting. This is truly facet grade rose quartz.
Quartz with Sphalerite and minor Pyrite. This specimen is a huge 12" X 13". Black Cloud Mine. Leadville Mining District. Leadville, Lake Co., Colo.
Geodes are small to large, subspherical to irregularly-shaped, crystal-lined cavities in rocks. They form when water enters a void in a host rock and precipitates crystals. The most common geode-lining mineral is quartz.