mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

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

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

Identified May 24, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from cooling of silica-rich magma or from hydrothermal veins. It is one of the most abundant minerals in the Earth's crust and can be found in almost all geological environments.

Uses & applications

Used in electronics (oscillators), optics, glassmaking, construction (as sandpaper or in concrete), and widely in jewelry and alternative healing practices.

Geological facts

Quartz is piezo-electric, meaning it generates an electric charge when mechanical pressure is applied. Ancient Greeks believed rock crystal was permanently frozen ice.

Field identification & locations

Identify in the field by its hardness (scratches glass), lack of cleavage, and hexagonal crystal habit. Found globally, especially in mountainous regions like the Alps, Arkansas (USA), and Brazil.