igneous
Snowflake Obsidian
Volcanic Glass with Spherulite inclusions (mainly Cristobalite)
Hardness: 5-5.5 (Mohs scale); Color: Black with white/gray patches; Luster: Vitreous/Glassy; Structure: Amorphous (glass) with snowflake-like inclusions of cristobalite; Cleavage: Conchoidal fracture
- Hardness
- 5-5
- Color
- Black with white/gray patches
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 5-5.5 (Mohs scale); Color: Black with white/gray patches; Luster: Vitreous/Glassy; Structure: Amorphous (glass) with snowflake-like inclusions of cristobalite; Cleavage: Conchoidal fracture
Formation & geological history
Formed from rapidly cooling felsic lava where partial crystallization or devitrification occurs, creating white 'snowflakes' of cristobalite within the glass.
Uses & applications
Used primarily in jewelry (beads, cabochons), ornamental carvings, decorative stones, and metaphysical practices.
Geological facts
The white 'snowflakes' are actually radial clusters of needle-like crystals of the mineral cristobalite, a high-temperature polymorph of silica.
Field identification & locations
Look for a glass-like texture with distinctive white blob-like or radial inclusions. Commonly found in volcanic areas like the Western United States (Utah, Oregon), Mexico, and Iceland.
