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Glittering
Stones >> Semi
Precious Stones >> Obsidian
Semi Precious Stone Obsidian
Top stone is obsidian, below that it is pumice
and in lower right hand is rhyolite (light color)Obsidian is one
type of naturally occurring glass, which produced from volcanoes
(igneous rock) when a fluid felsic lava cools rapidly and then
freezes without sufficient time for crystal growth,
for example by flowing into a body of the water. It consists mainly
of SiO2 (silicon dioxide), 80% or more. Obsidian is a mineral-like,
but not a true mineral because it is not a crystalline. Its composition
is very similar to that of granite and also rhyolite. It is sometimes
also classified as a mineral aid.
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Historical Facts of Obsidian
| Hardness |
5 - 6 |
| Chemical Composition |
70–75% SiO2, plus MgO, Fe3O4 |
| Density |
2.6 |
| Luster |
Vitreous |
| Color |
Black, Gray, Dark green, Red, Yellow, Pink |
| Occurrence |
Newberry Volcano, Medicine Lake Volcano of western
North America, Sierra Nevada of California, Yellowstone
National Park and other western US states |
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Gem Jewelry Obsidian
| Obsidian Bracelet |
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| Obsidian Earrings |
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| Obsidian Necklace |
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| Obsidian Rings |
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