igneous
Snowflake Obsidian
Spherulitic Obsidian (Volcanic glass containing Cristobalite)
AI-generated identification · may be incorrectHardness: 5-5.5 (Mohs scale), Color: Black with white-to-gray 'snowflakes', Luster: Vitreous/Glassy, Structure: Amorphous (non-crystalline glass with crystalline inclusions), Cleavage: None/Conchoidal fracture
- Hardness
- 5-5
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Physical properties
Hardness: 5-5.5 (Mohs scale), Color: Black with white-to-gray 'snowflakes', Luster: Vitreous/Glassy, Structure: Amorphous (non-crystalline glass with crystalline inclusions), Cleavage: None/Conchoidal fracture
Formation & geological history
Formed when felsic lava cools rapidly with minimal crystal growth. The 'snowflakes' are spherulites of white cristobalite crystals that grew within the glass during cooling or devitrification.
Uses & applications
Used primarily in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for collectors and metaphysical markets.
Geological facts
Although obsidian is a glass, the white patches are actually a form of quartz called cristobalite. Ancient cultures used obsidian for tools and weapons due to its razor-sharp conchoidal edges.
Field identification & locations
Identify by its distinctive black background and radiating white patterns; it feels smooth and glassy. Commonly found in volcanic areas like Utah (USA), Mexico, and Iceland.
