mineral

Quartz

Silicon Dioxide (SiO2)

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

Identified August 4, 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, clear to white or milky color, vitreous luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Formation & geological history

Forms in virtually all geological environments—igneous, metamorphic, and sedimentary rocks—often crystallizing from silica-rich hydrothermal solutions or cooling magma over millions of years.

Uses & applications

Widely used in electronics, glassmaking, oscillators, abrasive materials, gemstone carving, and ornamental jewelry.

Geological facts

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

Field identification & locations

Easily identified by its hardness (scratches glass), conchoidal fracture, and lack of cleavage. Found worldwide in riverbeds, pegmatites, and quartz veins.