mineral

Quartz (Milky and Bull Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White, translucent to opaque; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: White, translucent to opaque
Luster: Vitreous (glassy) to greasy

Identified March 24, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White, translucent to opaque; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. It is found in igneous, metamorphic, and sedimentary environments across all geological ages, from the Precambrian to Cenozoic.

Uses & applications

Used in glassmaking, abrasives, electronics (piezoelectric properties), construction (aggregate), and as gemstones or collector specimens.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is known as rock crystal, while the milky variety seen here is caused by tiny fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its ability to scratch glass, lack of cleavage, and waxy/glassy appearance. It is found globally in riverbeds, mountains, and beaches. Collectors should look for sharp crystal faces or clear points.

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