mineral

Tumbled quartz crystal

Quartz (silicon dioxide, SiO₂)

AI-generated identification · may be incorrect

Translucent colorless-to-milky gray, vitreous luster, irregular conchoidal fracture, and no obvious cleavage; Mohs hardness 7, hexagonal crystal structure, specific gravity about 2.65. The rounded edges indicate tumbling or natural abrasion.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, igneous melts, and metamorphic rocks; milky varieties contain microscopic fluid inclusions or fractures. Quartz is widespread and ranges from Precambrian to recent formations.

Uses & applications

Used for glass, ceramics, abrasives, electronics, and construction aggregate; clear attractive pieces are sold as specimens or lapidary material. This ordinary tumbled piece has modest commercial value.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge under pressure. Its apparent bubbles or cloudy patches are likely inclusions, fractures, or surface reflections rather than true bubbles.

Field identification & locations

Identify it by hardness— it should scratch glass but not be scratched by a steel knife—plus its glassy luster and conchoidal fracture. Common sources include Brazil, Madagascar, the United States, and quartz veins worldwide; acid testing is unnecessary.