mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness 7 on the Mohs scale, transparent to translucent clarity, vitreous (glassy) luster, trigonal crystal system, conchoidal fracture with no distinct cleavage, specific gravity of 2.65.

Identified July 23, 2026More mineral →

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Physical properties

Hardness 7 on the Mohs scale, transparent to translucent clarity, vitreous (glassy) luster, trigonal crystal system, conchoidal fracture with no distinct cleavage, specific gravity of 2.65.

Formation & geological history

Forms in a wide range of geological environments, most commonly in igneous pegmatites, hydrothermal veins, and metamorphic rocks as silica-rich fluids cool and crystallize.

Uses & applications

Widely used in jewelry, decorative carvings, metaphysical collections, and historically in optical lenses and frequency control electronics (piezoelectric applications).

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ancient Greeks believed clear quartz was ice that had frozen so deeply it could never thaw, calling it 'krustallos' (ice).

Field identification & locations

Identified by its hexagonal prism shape with pyramidal terminations, hardness capable of scratching glass, and lack of cleavage. Commonly found in pegmatite deposits, river gravels, and quartz veins worldwide (e.g., Arkansas, Brazil, Madagascar).