igneous
Snowflake obsidian
Volcanic glass (mostly rhyolitic) with cristobalite or feldspar spherulites
AI-generated identification · may be incorrectMohs hardness about 5–5.5; black, glossy, and commonly translucent at thin edges, with pale gray-white snowflake patterns. It has a glassy, noncrystalline structure, conchoidal fracture, no cleavage, and specific gravity around 2.35–2.60.
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Physical properties
Mohs hardness about 5–5.5; black, glossy, and commonly translucent at thin edges, with pale gray-white snowflake patterns. It has a glassy, noncrystalline structure, conchoidal fracture, no cleavage, and specific gravity around 2.35–2.60.
Formation & geological history
Forms when silica-rich lava cools rapidly, preventing crystallization; the snowflakes develop from radial cristobalite or feldspar aggregates during devitrification. Most commercial material formed in relatively young volcanic settings, especially in the Cenozoic.
Uses & applications
Commonly sold as tumbled stones, cabochons, beads, and ornamental objects; also used for lapidary study and decorative carving. It is generally inexpensive rather than a high-value gemstone.
Geological facts
The specimen’s rounded, polished shape indicates human processing, but it remains geological material. Pattern density and contrast vary widely within the same lava flow.
Field identification & locations
Identify by its black glassy body, conchoidal fracture, and distinctive gray-white rosettes; avoid confusing it with dyed glass or dalmatian jasper. Important sources include Oregon and California (USA), Mexico, and Armenia.
