mineral

Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified March 15, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in all types of geological environments; commonly crystallizes from cooling magma in igneous rocks like granite, or precipitates from hydrothermal veins. It can be found in rocks ranging from billions of years old to relatively young deposits.

Uses & applications

Extensively used in electronics (oscillators), optics, glass making, abrasives, and as a semi-precious gemstone in jewelry and metaphysical collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezo-electric, meaning it generates an electric charge in response to mechanical stress, which is why it is used in watches.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its lack of cleavage, and its characteristic horizontal striations on crystal faces. Found globally, especially in pegmatites and riverbeds as water-worn pebbles.