mineral

Likely polished dark pebble

Indeterminate; possibly basalt, black jasper, or a dark sulfide-rich stone

AI-generated identification · may be incorrect

Small, rounded, water-wet specimen with a dark gray-black color and scattered pale specks; apparent submetallic to glassy luster. Hardness cannot be determined reliably from the image; likely about Mohs 5–7 if basalt or jasper.

Identified August 7, 2026More mineral →

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Physical properties

Formation & geological history

The smooth shape may result from natural stream abrasion or tumbling. Basalt would be volcanic and commonly Cenozoic to Precambrian; jasper would form from silica-rich sediment or hydrothermal replacement.

Uses & applications

Usually a curiosity, teaching specimen, or polished pebble; dark jasper may be used in cabochons and carvings, while basalt is used mainly as aggregate and building stone.

Geological facts

The blue container and water enhance surface gloss and obscure diagnostic texture. A magnet, streak, hardness, and close inspection of grain size would be needed for confident identification.

Field identification & locations

Basalt commonly shows fine-grained texture and may attract a weak magnet; jasper has a dense, opaque, waxy appearance and leaves a white streak. Common sources include river gravels, volcanic terrains, and commercial tumbling mixes.