igneous
Polished black-and-white stone, possibly snowflake obsidian
Likely obsidian (volcanic glass); exact identification is uncertain from the photo
AI-generated identification · may be incorrectSmall, rounded, polished pebble with a glossy black surface and pale gray-white patches. If obsidian, hardness is about 5–5.5 Mohs and its structure is amorphous, not crystalline; the pale markings are not clearly diagnostic here.
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Physical properties
Small, rounded, polished pebble with a glossy black surface and pale gray-white patches. If obsidian, hardness is about 5–5.5 Mohs and its structure is amorphous, not crystalline; the pale markings are not clearly diagnostic here.
Formation & geological history
Obsidian forms when silica-rich lava cools rapidly, typically at volcanic flows; the pictured pebble may have been tumbled from natural material. Its age and source cannot be determined from the image.
Uses & applications
Tumbled stones are used in jewelry, crafts, and collections; raw obsidian has also been used for sharp cutting tools.
Geological facts
Snowflake obsidian is black volcanic glass with pale spherulites, commonly cristobalite, but this specimen’s markings are too limited to confirm that variety.
Field identification & locations
Check for glassy luster and conchoidal fracture; natural snowflake patterns are usually distinct pale, radiating clusters. Obsidian occurs in volcanic regions, including Mexico and the western United States.
