igneous
Silver Sheen Obsidian
Volcanic Glass (SiO2)
Hardness: 5-5.5, Color: Black/Gray with silver-metallic luster, Luster: Vitreous to sub-metallic, Crystal Structure: Amorphous
- Hardness
- 5-5
- Luster
- Vitreous to sub-metallic, Crystal Structure: Amorphous
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Physical properties
Hardness: 5-5.5, Color: Black/Gray with silver-metallic luster, Luster: Vitreous to sub-metallic, Crystal Structure: Amorphous
Formation & geological history
Formed by the rapid cooling of silica-rich rhyolitic lava which prevents crystal growth. The sheen is caused by tiny bubbles of gas trapped during solidification.
Uses & applications
Commonly used in jewelry (cabochons), ornamental carvings, and historical tool making (knapping).
Geological facts
Due to its lack of crystal structure, obsidian breaks with a conchoidal fracture that creates edges sharper than surgical steel.
Field identification & locations
Identified by its glass-like texture and the distinct silvery reflection that appears when tilted under direct light. Often found in volcanic fields.
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