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> Minerals
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Obsidian
is not a mineral but volcanic glass formed as an extrusiv igneous rock. Obsidian is a mixture of amorphouse or cryptocrystalline grains of silica minerals formed as a result of quickly cooled lava. Petrograficaly belong the obsidian to the rhyolit-dacit family.
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| Synonyms: |
Bergmahogany, Black Lava Glass, Hyalopsite, Isophyre, Xaga |
| Varieties: |
Fire Obsidian, Mahogany Obsidian, rainbow Obsidian, Sheen Obsidian, Snowflake Obsidian |
| Classification: |
Igneous rock, volcanic glass, rhyolit-dacit family |
| Tenacity: |
Brittle |
| Fracture: |
Conchoidal |
| Colour: |
Black, grey, green, reddisch, bluish, mahogany, golden, peacock |
| Lustre: |
Vitreous |
| Transparency: |
Translucent |
| Application: |
Gemstone |
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Superior, Pinal County, Arizona, USA
