mineral

Possibly tumbled black stone (uncertain; may be black glass or obsidian)

Undetermined; possible obsidian (natural volcanic glass, predominantly SiO₂)

AI-generated identification · may be incorrect

Small, smooth, opaque black piece with a glossy surface and rounded edges. Hardness, streak, and internal structure cannot be determined from the photograph; its polish could also indicate manufactured glass or another stone.

Identified October 1, 2026More mineral →

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Physical properties

Formation & geological history

If obsidian, it formed when silica-rich lava cooled rapidly, usually in geologically young volcanic settings. The image alone cannot establish its age or confirm its natural origin.

Uses & applications

Tumbled black stones are commonly used in jewelry, crafts, and collecting; obsidian has also been used historically for sharp tools.

Geological facts

Obsidian is volcanic glass rather than a crystalline mineral and can break with sharp, curved (conchoidal) fractures.

Field identification & locations

A photo is insufficient for reliable identification. Check for bubbles or uniform glass-like texture, and use hardness and fracture tests cautiously; common possibilities include obsidian, onyx, or glass.