mineral

Tumbled quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent white to colorless, with a vitreous-to-waxy luster and indistinct internal fractures. It has a trigonal crystal structure but no cleavage, breaking with conchoidal fracture; specific gravity is about 2.65.

Identified September 15, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich igneous, hydrothermal, and metamorphic fluids, commonly forming in veins and pegmatites over broad geologic timescales. The rounded shape and smooth surface indicate human tumbling and polishing rather than natural crystal growth.

Uses & applications

Used as a decorative/collecting stone, in carvings and cabochons, and industrially for glass, ceramics, abrasives, and engineered stone; this specimen has mainly ornamental value.

Geological facts

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

Field identification & locations

Identify it by its glassy translucence, lack of cleavage, conchoidal fracture, and ability to scratch ordinary glass; a steel file will not scratch it. Common sources include Brazil, Madagascar, the United States, and worldwide quartz veins.