Mineral

Quartz (Clear / Rock Crystal)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

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 March 29, 2026More mineral →

Explore Quartz (Clear / Rock Crystal) in the encyclopedia →

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. Typically crystallizes from cooling magma or precipitates from hydrothermal veins. It has been forming throughout Earth's geological history.

Uses & applications

Used in electronics (oscillators), glassmaking, abrasives, construction (as silica sand), jewelry, and as a popular collector's mineral.

Geological facts

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

Field identification & locations

Identify in the field by its hardness (it can scratch glass), lack of cleavage, and hexagonal crystal points. Found globally, especially in mountain ranges like the Alps or the Appalachians.