Snowflake Obsidian

Physical Properties

Hardness: 5-5.5 (Mohs); Color: Black with white or gray 'snowflake' patches; Luster: Vitreous/Glassy; Structure: Amorphous (non-crystalline matrix); Cleavage: None/Conchoidal fracture; SG: 2.35-2.60

Formation & Geological History

Formed through the rapid cooling of silica-rich rhyolitic lava. The 'snowflakes' are spherulites of cristobalite (a silica polymorph) that grew as the glass cooled or underwent devitritication.

Uses & Applications

Used primarily for ornamental carvings, jewelry (cabochons and beads), and as a popular specimen for metaphysical or lapidary collectors.

Geological Facts

Unlike crystalline rocks, obsidian is technically a mineraloid. The 'snowflake' pattern is actually a form of partial crystallization known as devitrification, where crystals grow in a radial pattern within the glass.

Field Identification & Locations

Identify by its glassy texture, sharp conchoidal (shell-like) fractures, and distinct radial white clusters. Commonly found in volcanic regions such as Utah and California (USA), Iceland, and Mexico.

Identified on: 4/23/2026

Mode: Standard