Clear Quartz (Rock Crystal)

Physical Properties

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

Formation & Geological History

Forms in a wide variety of environments, most commonly from the cooling of silica-rich magma or through hydrothermal activity where mineral-rich hot water deposits crystals in rock veins and cavities.

Uses & Applications

Used in electronics for its piezoelectric properties, glass manufacturing, abrasives, jewelry (gemstones), and as a popular decorative or healing specimen for collectors.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is traditionally called rock crystal; the name comes from the Greek word 'krystallos', meaning ice, as ancients believed it was ice frozen so hard it would never melt.

Field Identification & Locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage, and characteristic six-sided prismatic crystals. It is ubiquitous worldwide, with notable high-quality deposits in Brazil, Arkansas (USA), and the Alps.

Identified on: 4/23/2026

Mode: Standard