mineral

Quartz

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, typically white, milky, or translucent with a vitreous to greasy luster, hexagonal crystal system, and conchoidal fracture with no true cleavage. Specific gravity is approximately 2.65.

Identified August 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed in a wide variety of geological environments including igneous, metamorphic, and sedimentary rocks. It is a primary component of pegmatites, hydrothermal veins, and sandstones, and crystallizes out of silica-rich solutions over geological timescales.

Uses & applications

Widely used in electronics, oscillators, glassmaking, abrasives, construction materials, and as a gemstone or decorative mineral specimen in jewelry and lapidary arts.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust, surpassed only by feldspar. Due to its piezoelectric properties, quartz crystals are used to regulate frequencies in electronic devices such as watches and radios.

Field identification & locations

Easily identifiable in the field by its characteristic hardness (scratches glass), lack of cleavage, conchoidal fracture, and hexagonal crystal habit when well-formed. It is found worldwide in almost every geological setting.