mineral

Quartz (Milky or Cloudy)

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: White to off-white, translucent to opaque
Luster: Vitreous to greasy

Identified June 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed via igneous crystallization from magma or hydrothermal precipitation from hot, mineral-rich fluids in veins. It is found in a wide variety of geological ages and environments, from ancient metamorphic shields to recent volcanic deposits.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, as a flux in metallurgy, and as an ornamental stone or collector's specimen.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but milky quartz gets its cloudy appearance from minute fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage, and typical crystal habits. It is found worldwide in almost all geological settings, especially in gravel beds, mountain ranges, and as vein fillings.