igneous
Polished black-and-white banded stone, possibly snowflake obsidian
Likely obsidian (volcanic glass; SiO₂-rich), though the image is insufficient to confirm the material or identify its patterning
AI-generated identification · may be incorrectPolished, glossy black areas contrast with translucent gray-white bands. If obsidian, it has no true crystal structure, conchoidal fracture, and hardness about 5–5.5 Mohs; the visible texture may indicate another stone or an inclusion-rich specimen.
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Physical properties
Polished, glossy black areas contrast with translucent gray-white bands. If obsidian, it has no true crystal structure, conchoidal fracture, and hardness about 5–5.5 Mohs; the visible texture may indicate another stone or an inclusion-rich specimen.
Formation & geological history
Obsidian forms when silica-rich lava cools rapidly, commonly in volcanic regions; its age depends on the deposit. The specimen appears shaped and polished.
Uses & applications
Decorative display and collecting; obsidian is also used for beads and carvings, and historically for sharp-edged tools.
Geological facts
Snowflake obsidian has pale spherulites of cristobalite in a dark glassy matrix, usually forming distinct spots rather than broad bands.
Field identification & locations
Check for glassy luster and curved, shell-like fracture on an unpolished edge; banding alone does not establish obsidian. Obsidian occurs in volcanic areas, including the western United States, Mexico, and Iceland.
