mineral

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; colorless to smoky-clear, vitreous luster, translucent, and typically hexagonal/trigonal crystal structure. Quartz has no true cleavage and shows conchoidal fracture; the specimen appears naturally terminated but somewhat abraded or coated.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms from silica-rich hydrothermal fluids, pegmatites, and cavities in igneous or metamorphic rocks; quartz crystallized throughout Earth’s history, commonly in veins and geodes.

Uses & applications

Used for glass, electronics, optics, abrasives, countertops, and gemstone/collector specimens. Clear, well-formed crystals have modest display value.

Geological facts

Quartz is piezoelectric and can generate an electrical potential when mechanically stressed. Its pointed termination and hardness distinguish it from many similar clear minerals.

Field identification & locations

Common worldwide, especially in Brazil, Madagascar, Arkansas, the Alps, and pegmatite districts. Identify by hardness, glassy luster, lack of cleavage, and—if visible—a six-sided prismatic form with pyramidal termination.