mineral

Tumbled quartz pebble

Quartz (SiO₂), likely iron-stained or included quartz

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent tan-brown to gray with a vitreous-to-waxy luster and irregular internal fractures/inclusions. Quartz is trigonal and lacks cleavage, showing conchoidal fracture; specific gravity about 2.65.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich fluids crystallized in veins or cavities, then weathering and stream abrasion rounded the piece; its exact geological age and source cannot be determined from the image. Brown coloration likely comes from iron-oxide staining.

Uses & applications

Commonly sold as a decorative or collecting stone and used in lapidary work, cabochons, and tumbling; quartz is also important industrially in glass, ceramics, electronics, and abrasives.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge under pressure.

Field identification & locations

Identify it by its glassy translucence, rounded tumbled form, lack of cleavage, and ability to scratch ordinary glass; a steel blade should not scratch it. Common sources include hydrothermal veins and river gravels worldwide.