mineral

Quartz

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, clear or transparent color (Rock Crystal), vitreous (glassy) luster, hexagonal crystal system, conchoidal fracture with no true cleavage, and a specific gravity of 2.65.

Identified August 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed in a wide variety of geological environments, most commonly crystallized from silica-rich hydrothermal veins, pegmatites, and as a primary component of igneous, metamorphic, and sedimentary rocks.

Uses & applications

Used widely in electronics (oscillators, quartz clocks), glassmaking, abrasives, gemstones, and ornamental carvings.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust, surpassed only by feldspar. It exhibits piezoelectric properties, meaning it can generate an electrical charge in response to mechanical stress.

Field identification & locations

Easily identified by its distinct hexagonal prism crystal habit, high hardness (scratches glass easily), and lack of cleavage. Found globally, with notable deposits in Brazil, the USA, Madagascar, and the Alps.