igneous
Snowflake Obsidian
Volcanic glass with Spherulite inclusions (SiO2)
Hardness: 5-6 (Mohs); Color: Black with white/grey 'snowflake' patches; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline matrix); Cleavage: None/Conchoidal fracture.
- Hardness
- 5-6 (Mohs)
- Color
- Black with white/grey 'snowflake' patches
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 5-6 (Mohs); Color: Black with white/grey 'snowflake' patches; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline matrix); Cleavage: None/Conchoidal fracture.
Formation & geological history
Formed from rapidly cooling felsic lava where water or certain minerals undergo devitrification, forming radial clusters of cristobalite crystals (the snowflakes). Found in volcanic regions.
Uses & applications
Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for rock collectors and metaphysical healers.
Geological facts
The white 'snowflakes' are actually radial clusters of white cristobalite crystals growing within the obsidian glass. It has been used for millennia to make cutting tools and arrowheads.
Field identification & locations
Identify by its glass-like texture, sharp conchoidal edges when broken, and distinctive white internal spots. Commonly found in areas of recent volcanic activity such as Utah or Iceland.
