mineral

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 March 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

Quartz forms in a wide variety of environments, most commonly from the cooling of silica-rich magma or from hydrothermal veins. It is found in igneous, metamorphic, and sedimentary rocks across all geological ages.

Uses & applications

Used extensively in glass manufacturing, electronics (due to piezoelectric properties), construction sands, and as gemstones in jewelry or for metaphysical/collecting purposes.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz'. If the crystal is perfectly clear, it is often called 'Rock Crystal'.

Field identification & locations

Identify in the field by its ability to scratch glass (hardness 7), its lack of cleavage, and its characteristic conchoidal (shell-like) fracture. Commonly found in granite outcrops, riverbeds, and quartz veins.