mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless/transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified June 7, 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: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in igneous, metamorphic, and sedimentary environments through the cooling of silica-rich magma or precipitation from hydrothermal veins. Often found in pegmatites and geyser deposits.

Uses & applications

Used in electronics for oscillators, watches (piezoelectric properties), glassmaking, optical instruments, and widely as gemstones or decorative points for collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Historically, the Greeks believed clear quartz was ice that had frozen so hard it could never melt.

Field identification & locations

Identify in the field by its 6-sided crystal habit, its ability to scratch glass (hardness 7), and the lack of cleavage. Common in Arkansas (USA), Brazil, and Madagascar.