Clear Quartz (Rock Crystal)

Physical Properties

Hardness: 7 on the Mohs scale. Color: Colorless/Transparent. Luster: Vitreous (glass-like). Crystal structure: Trigonal/Hexagonal. Cleavage: Indistinct/Conchoidal fracture. Specific gravity: 2.65.

Formation & Geological History

Formed through the cooling of silica-rich magma or precipitation from hydrothermal veins. It occurs in all types of geological environments (igneous, metamorphic, and sedimentary) and can be found in rocks from almost every geological age.

Uses & Applications

Used in electronics (oscillators), optics, glassmaking, and abrasive manufacturing. Highly popular in jewelry, carvings, and as a collector's mineral specimen.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezoelectric, meaning it generates an electric charge when mechanical pressure is applied, which led to its use in quartz watches.

Field Identification & Locations

Identify in the field by its hardness (will scratch glass and steel), its conchoidal (shell-like) fracture, and lack of true cleavage. It is found globally, with significant deposits in Brazil, Arkansas (USA), and the Alps.

Identified on: 4/22/2026

Mode: Standard