mineral

Tumbled quartz-rich pebble, possibly smoky quartz or chert

Quartz (SiO₂), or microcrystalline quartz if chert

AI-generated identification · may be incorrect

Translucent brownish-gray body with a waxy to vitreous luster and indistinct internal fractures; likely hardness Mohs 7 if crystalline quartz, about 6.5–7 if chert. Quartz has a trigonal crystal structure and no cleavage, breaking conchoidally; specific gravity is about 2.65.

Identified August 29, 2026More mineral →

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Physical properties

Formation & geological history

Likely a naturally rounded and human-tumbled silica-rich pebble, formed in a quartz vein or sedimentary chert deposit. Its exact geological age and source cannot be determined from the image.

Uses & applications

Common material for lapidary tumbling, décor, and inexpensive collectible specimens; quartz varieties may also be used in glass, ceramics, electronics, and jewelry.

Geological facts

The brown color may result from iron staining or radiation-induced smoky coloration. The smooth shape and uniformly polished surface indicate processing rather than a naturally weathered crystal.

Field identification & locations

Test an inconspicuous area with a steel file or glass: true quartz should scratch glass and resist steel. Common sources include quartz veins, river gravels, and chert-bearing sedimentary regions.