mineral

Quartz

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, white to clear color, vitreous to greasy luster, hexagonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Identified August 1, 2026More mineral →

Explore Quartz in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness of 7 on the Mohs scale, white to clear color, vitreous to greasy luster, hexagonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Formation & geological history

Forms in a wide variety of geological environments, including igneous, metamorphic, and sedimentary rocks. It crystallizes from silica-rich hydrothermal solutions and magma, and is very resistant to weathering.

Uses & applications

Used in glassmaking, electronics, oscillators, abrasives, gemstones, and decorative items.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust, surpassed only by feldspar. Its piezoelectric properties make it essential for keeping time in watches.

Field identification & locations

Identified in the field by its hardness (scratches glass easily), lack of cleavage, and conchoidal fracture. Commonly found worldwide in pegmatites, veins, and as sand in sedimentary deposits.