mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Colorless/Transparent
Luster: Vitreous (glassy)

Identified June 27, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Quartz forms in a wide variety of environments, most commonly by crystallizing from molten magma as it cools (igneous) or by precipitating from hot hydrothermal veins. It is found in rocks from all geological ages.

Uses & applications

Extensively used in jewelry and decorative carvings, glassmaking, electronics (piezoelectric properties), and as a popular specimen for collectors and metaphysical use.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is traditionally called rock crystal or clear quartz and has been used since antiquity for hardstone carving.

Field identification & locations

Identified by its ability to scratch glass (hardness 7), its lack of cleavage (it breaks like glass), and its hexagonal crystal habit. Found globally in granites and pegmatites.