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Obsidian
| Chemical Composition |
Naturally occurring volcanic glass (molten silica). |
| Colour |
Black, gray, sometimes iridescent. |
| Refractive Index |
R.I. 1.49. |
| Durability |
Hardness 5-6. Brittle and heat sensitive. |
| Crystal Structure |
Amorphous |
| Specific Gravity |
2.3-3.0. |
| Sources / Occurrence |
Found in locations of volcanic activity (past or present) -- New Mexico, Hawaii, Mexico, Wyoming (Yellowstone), Utah, Japan, Iceland. |
| Varieties |
Rainbow Obsidian
Snow- flake Obsidian | | |
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