igneous
Snowflake obsidian
Volcanic glass (mostly silica-rich obsidian) with cristobalite spherulites
AI-generated identification · may be incorrectBlack, glassy to polished, with pale gray-white snowflake-like spots; hardness about 5–5.5 Mohs, amorphous structure, and conchoidal fracture in unworked pieces. The pictured beads are cut and polished; their exact mineral makeup cannot be confirmed visually.
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Physical properties
Black, glassy to polished, with pale gray-white snowflake-like spots; hardness about 5–5.5 Mohs, amorphous structure, and conchoidal fracture in unworked pieces. The pictured beads are cut and polished; their exact mineral makeup cannot be confirmed visually.
Formation & geological history
Forms when silica-rich lava cools rapidly, preventing crystals from growing; snowflake patterns develop as cristobalite spherulites within the glass. It is associated with relatively young volcanic deposits, though obsidian occurs across many geological ages.
Uses & applications
Commonly cut into beads, cabochons, and carvings; also collected as a decorative volcanic rock.
Geological facts
The spots are radial mineral aggregates, not flakes or fossils, and their contrast creates the characteristic snowflake pattern.
Field identification & locations
Look for sharply contrasting pale, flower-like patches in a black glassy matrix; major sources include the western United States, Mexico, and other volcanic regions. These beads appear consistent with snowflake obsidian, but visual identification is not definitive.
