mineral

Quartz (Milky/Smoky variety on matrix)

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: White to brownish
Luster: Vitreous (glassy) to greasy

Identified March 21, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through the cooling of magma or precipitation from hydrothermal veins. This specimen shows a mix of milky quartz with some smoky/brown staining, likely associated with a host rock matrix of granite or gneiss.

Uses & applications

Common varieties are used as industrial abrasives, in glassmaking, and in electronics (piezoelectric properties). Specimens like these are primarily for entry-level hobbyist collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to both chemical and physical weathering, which is why it is often found as loose pebbles and sand.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage (it breaks in irregular, curved shards like glass). Common worldwide in nearly all geological environments.

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