mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal/Trigonal (terminating in a six-sided pyramid); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

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

Identified July 12, 2026More mineral →

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Physical properties

Formation & geological history

Formed from cooling magma or hydrothermally in veins and geodes. It is found in all types of rock (igneous, metamorphic, and sedimentary) across a wide range of geological ages.

Uses & applications

Used in electronics (oscillators), optical instruments, jewelry, glassmaking, abrasive materials, and as a popular metaphysical or decorative collectable.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure clear quartz is known as 'Rock Crystal' and was once believed by ancient Greeks to be ice that had frozen so hard it would never melt.

Field identification & locations

Identify in the field by its hardness (scratches glass), lack of cleavage, and prismatic crystal shape with horizontal striations on the faces. Commonly found in mountainous regions globally, notably Arkansas (USA), Brazil, and Madagascar.