igneous

Snowflake Obsidian

Volcanic glass containing Spherulites (SiO2)

Hardness: 5-5.5 (Mohs scale), Color: Black with white or gray patches, Luster: Vitreous/Glassy, Crystal Structure: Amorphous (glassy) with cristobalite inclusions, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.35-2.6

Hardness: 5-5

Identified April 12, 2026More igneous →

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Physical properties

Formation & geological history

Formed from rapidly cooling rhyolitic lava. The 'snowflakes' are spherulites, which are radial clusters of needle-like cristobalite crystals that form as the glass begins to devitrify.

Uses & applications

Used in jewelry (cabochons, beads), decorative carvings, meditation stones, and as a collector's specimen.

Geological facts

Snowflake obsidian is unique because it represents a stage of 'aging' for volcanic glass; over geological time, most obsidian will eventually crystallize completely. It was historically used for making sharp tools and arrowheads.

Field identification & locations

Identify by its distinctive white 'snowflake' patches against a jet-black glassy background. It is commonly found in volcanic regions of the United States (Utah, Oregon), Mexico, and Iceland.

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Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

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Magnetite (Fe3O4)

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