| Chemical
Composition |
Naturally
occurring volcanic glass (molten silica). |
| Color |
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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