mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

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

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

Identified July 13, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in igneous, metamorphic, and sedimentary environments through the cooling of silica-rich magma or precipitation from hydrothermal veins. Found in rocks of all geological ages.

Uses & applications

Used in electronics (oscillators), optical instruments, glass manufacturing, abrasives, jewelry, and as a popular collector's specimen.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure clear quartz is known as 'Rock Crystal' and was once believed by ancient Greeks to be ice that had frozen so hard it would never melt.

Field identification & locations

Identify by its hardness (scratches glass but not topaz), its lack of cleavage, and its characteristic hexagonal crystal habit if faces are present. Commonly found in pegmatites and riverbeds.