igneous
Snowflake Obsidian
Vitreous Volcanic Rock (Amorphous Silicate), SiO2
Hardness: 5–5.5 on Mohs scale; Color: Black with white-to-gray 'snowflake' patterns; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline); Cleavage: Conchoidal fracture; Gravity: 2.35–2.6.
- Hardness
- 5–5
- Color
- Black with white-to-gray 'snowflake' patterns
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 5–5.5 on Mohs scale; Color: Black with white-to-gray 'snowflake' patterns; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline); Cleavage: Conchoidal fracture; Gravity: 2.35–2.6.
Formation & geological history
Formed through the rapid cooling of silica-rich felsic lava which prevents crystal growth. The 'snowflakes' are inclusions of the mineral cristobalite (a polymorph of silica) that underwent devitrification over geological time.
Uses & applications
Commonly used in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for collectors and holistic practitioners.
Geological facts
Obsidian was prized in antiquity for making extremely sharp blades and arrowheads because of its conchoidal fracture. The white patches in this variety are technically spherulites of cristobalite.
Field identification & locations
Identify by its glass-like texture and distinct white radiating patterns on a black background. Found in volcanic regions like the United States (Utah, Oregon), Mexico, and Iceland. Authentic specimens will scratch regular glass and feel slightly lighter than quartz.
