mineral

Tumbled milky quartz (likely iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; cream to translucent white with yellow-brown iron-oxide staining, vitreous to waxy luster, and no obvious cleavage. It has a trigonal crystal structure, though tumbling has rounded its surfaces; specific gravity is about 2.65.

Identified August 13, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, or igneous and metamorphic rocks; brown coloration commonly develops through later oxidation of iron-bearing inclusions. Quartz is widespread from Precambrian to modern geological settings.

Uses & applications

Used for decorative stones, tumbling, carvings, countertops, glass, ceramics, and electronics; attractive translucent pieces have modest lapidary and collecting value.

Geological facts

The specimen appears water-worn or mechanically tumbled and may contain limonite/goethite inclusions. A steel file should not scratch quartz, while quartz can scratch ordinary glass.

Field identification & locations

Common worldwide, including Brazil, Madagascar, the United States, and many gravel deposits. Confirm with a hardness test and inspect for glassy fracture, rather than relying on color alone.