mineral

Clear quartz (rock crystal)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Typically colorless to translucent with a vitreous luster, conchoidal fracture, and no cleavage; Mohs hardness 7, trigonal crystal structure, specific gravity about 2.65. The irregular shape may indicate a broken or naturally water-worn piece.

Identified September 7, 2026More mineral →

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Physical properties

Formation & geological history

Forms from silica-rich hydrothermal fluids, cavities in igneous rocks, and metamorphic veins; quartz spans much of Earth’s geological history, from Precambrian rocks to modern deposits.

Uses & applications

Used in glass, ceramics, abrasives, electronics, and timekeeping; transparent crystals are collected and occasionally cut as gemstones. This small, rough specimen has minimal commercial value.

Geological facts

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

Field identification & locations

Identify by its glassy appearance, hardness sufficient to scratch ordinary glass, and lack of cleavage; common localities include Brazil, Madagascar, the Alps, Arkansas, and many worldwide vein deposits. A hardness or streak test should be performed inconspicuously.