mineral

Polished black stone, possibly obsidian

Undetermined; if obsidian, natural volcanic glass (silica-rich, chiefly SiO₂)

AI-generated identification · may be incorrect

Glossy black surface and curved, polished form; hardness and internal structure cannot be determined from the image. It could also be another dark stone or a coated material.

Identified October 2, 2026More mineral →

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Physical properties

Glossy black surface and curved, polished form; hardness and internal structure cannot be determined from the image. It could also be another dark stone or a coated material.

Formation & geological history

The specimen is too obscured to identify its material or formation. Obsidian forms when silica-rich lava cools rapidly, typically in volcanic settings.

Uses & applications

Possibly a polished decorative or jewelry stone; exact uses depend on identification.

Geological facts

Obsidian commonly breaks with sharp, curved (conchoidal) fractures and lacks a crystalline structure.

Field identification & locations

The smooth, reflective exterior is not diagnostic. Inspect an uncoated edge and fracture, or test hardness and streak; avoid assuming it is obsidian from color alone.