Colour change nature
Opal is a color-change stone. When you spin the stone around, colours might appear or disappear, or change completely. It's quite magical. This is NOT a gem-quality opal, rather it's a boulder opal, because the opal veins are embedded in a brownstone called ironstone.
Had the entire stone displayed the colourful patches, this stone would have costed probably USD $8,000 and up!
xxxxxx
Of all the beautiful and expensive gemstones that I cannot afford, opal is the one that I like the most.
High-quality precious black opals from Australia can cost easily between USD $5,000 to $15,000 each. Opal is a natural amorphous silica with a water content varying from one to twenty percent, depending on the porosity and degree of hydration. Precious opal usually contains from six to ten percent water. The chemical formula for opal is SiO2·nH2O.
Thankfully I came across this boulder opal for only USD $14. I can afford that!
Basically, a boulder opal is an opal embedded in a brown rock called ironstone, like the one you see here. Had the entire gemstone displayed the colourful and colour-changing nature, this opal would have been worth probably around USD $8,000. But because only very few stripes (known as veins) display the colourful diffraction of light, this stone is not considered gem-quality, which is why it goes for less than USD $100. In my case, bidding ended at USD $14 so I was quite lucky.
Some interesting facts about opal:
1) Green and blue play of colour is most common, red less so.
2) Because of the unusual way opal is formed, and how light is diffracted from it, colour may appear or disappear under different light sources, or may change from one colour to another completely.
3) Depending on the play of colour, the value of an opal can vary significantly.
4) As a natural silica, opals are very fragile. Drop it on a hard surface and cracks can appear, or worse still, the whole piece might shatter.
Also remember, this opal only measures 17.2 mm x 12.1 mm, so the photos shown here have been magnified by 3 times, if not more.
The seller of the opals on eBay post videos of the stones. And this is a video of the stone I bought.
Colour change nature
Opal is a color-change stone. When you spin the stone around, colours might appear or disappear, or change completely. It's quite magical. This is NOT a gem-quality opal, rather it's a boulder opal, because the opal veins are embedded in a brownstone called ironstone.
Had the entire stone displayed the colourful patches, this stone would have costed probably USD $8,000 and up!
xxxxxx
Of all the beautiful and expensive gemstones that I cannot afford, opal is the one that I like the most.
High-quality precious black opals from Australia can cost easily between USD $5,000 to $15,000 each. Opal is a natural amorphous silica with a water content varying from one to twenty percent, depending on the porosity and degree of hydration. Precious opal usually contains from six to ten percent water. The chemical formula for opal is SiO2·nH2O.
Thankfully I came across this boulder opal for only USD $14. I can afford that!
Basically, a boulder opal is an opal embedded in a brown rock called ironstone, like the one you see here. Had the entire gemstone displayed the colourful and colour-changing nature, this opal would have been worth probably around USD $8,000. But because only very few stripes (known as veins) display the colourful diffraction of light, this stone is not considered gem-quality, which is why it goes for less than USD $100. In my case, bidding ended at USD $14 so I was quite lucky.
Some interesting facts about opal:
1) Green and blue play of colour is most common, red less so.
2) Because of the unusual way opal is formed, and how light is diffracted from it, colour may appear or disappear under different light sources, or may change from one colour to another completely.
3) Depending on the play of colour, the value of an opal can vary significantly.
4) As a natural silica, opals are very fragile. Drop it on a hard surface and cracks can appear, or worse still, the whole piece might shatter.
Also remember, this opal only measures 17.2 mm x 12.1 mm, so the photos shown here have been magnified by 3 times, if not more.
The seller of the opals on eBay post videos of the stones. And this is a video of the stone I bought.