mineral

Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Clear to yellowish/tan (common); Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None (Conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Clear to yellowish/tan (common)
Luster: Vitreous

Identified July 1, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Clear to yellowish/tan (common); Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None (Conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Forms through crystallization of magma or precipitation from hydrothermal veins. Often found in continental crust and as a primary component of many igneous, sedimentary, and metamorphic rocks.

Uses & applications

Used in jewelry, watchmaking (quartz crystals for timekeeping), glass manufacturing, electronics, and as a semi-precious collector's specimen.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which may be of Slavic origin. It is piezoelectric, meaning it generates an electric charge in response to applied mechanical stress.

Field identification & locations

Identify by its hardness (will scratch glass), lack of cleavage, and characteristic greasy/glassy luster. To the untrained eye, yellowish quartz is often mistaken for citrine or topaz, but it is much more common and found in streambeds and outcrops worldwide.