mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Colorless and transparent. Luster: Vitreous (glassy). Crystal structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Colorless and transparent
Luster: Vitreous (glassy)

Identified July 12, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale. Color: Colorless and transparent. Luster: Vitreous (glassy). Crystal structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Formation & geological history

Forms in a wide variety of geological environments, most commonly from cooling magma in igneous rocks like granite or from hydrothermal veins. It can form at various temperatures and pressures throughout geological history.

Uses & applications

Used in jewelry, carvings, and as a decorative gemstone. Due to its piezoelectric properties, it is also used in electronics (oscillators and clocks) and glassmaking.

Geological facts

Clear quartz, also known as Rock Crystal, comes from the Greek word 'krystallos' meaning ice. It was once believed to be ice that had frozen so hard it would never melt. It is the second most abundant mineral in Earth's continental crust.

Field identification & locations

Identify by its transparency, 7.0 hardness (will scratch glass but not topaz), and lack of cleavage. It is found globally, with major deposits in Brazil, Madagascar, and the United States (Arkansas). Collectors look for clarity and well-defined crystal faces.