igneous
Snowflake Obsidian
Vitreous Silica with Spherulite inclusions (Amorphous SiO2)
Hardness: 5-5.5 (Mohs scale); Color: Black with white or light gray spots; Luster: Vitreous/Glassy; Structure: Amorphous (glass); Specific Gravity: 2.35-2.6.
- Hardness
- 5-5
- Color
- Black with white or light gray spots
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 5-5.5 (Mohs scale); Color: Black with white or light gray spots; Luster: Vitreous/Glassy; Structure: Amorphous (glass); Specific Gravity: 2.35-2.6.
Formation & geological history
Formed from rapidly cooling felsic lava where water or minerals did not have time to crystallize into a stone. The 'snowflakes' are inclusions of cristobalite (a type of quartz) that grew in a radial pattern (spherulites).
Uses & applications
Used primarily in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for rock collectors and metaphysical use.
Geological facts
The white spots are actually internal devitrification where the glass has begun to turn into crystalline quartz. It was used by ancient civilizations for making sharp tools and arrowheads.
Field identification & locations
Identify by its characteristic white radial inclusions on a dark glassy black base. Commonly found in volcanic regions such as the Western United States, Mexico, and Iceland.
