Snowflake Obsidian

Physical Properties

Hardness: 5-5.5 (Mohs scale); Color: Black with grayish-white 'snowflakes'; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline glass) with spherulite inclusions; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.3-2.6

Formation & Geological History

Formed when silica-rich lava undergoes rapid cooling that prevents crystal growth, creating glass. The white 'snowflakes' are spherulites of the mineral cristobalite, which form through partial devitrification of the glass over time.

Uses & Applications

Primarily used for ornamental purposes such as gemstones, beads, cabochons, carvings, and metaphysical collecting. Historically, obsidian was used for sharp tools and blades.

Geological Facts

Obsidian isn't technically a mineral because it is a glass (amorphous) and has no set crystalline structure, though it is often studied in mineralogy. The white patches are actually a form of quartz called cristobalite.

Field Identification & Locations

Identify in the field by its distinct conchoidal fracture (curved, shell-like breaks) and the presence of white, radial patterns against a black glassy background. It is commonly found in areas of recent volcanic activity, such as Utah (notably Black Rock Desert) and parts of Mexico.

Identified on: 4/19/2026

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