mineral

Quartz (Milky or Cloudy variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White, grayish-white, or translucent with reddish-brown iron staining; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the crystallization of silica-rich magma or precipitation from hydrothermal fluids. This specimen appears to be 'bull quartz' from a hydrothermal vein, common in various geological eras including the Precambrian to Cenozoic.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), abrasives, and as construction aggregate. Massive varieties are used in landscaping and as low-cost decorative garden stones.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. 'Milky' quartz gets its opacity from tiny fluid inclusions of gas and/or liquid trapped during crystal growth.

Field identification & locations

Identify by its ability to scratch glass (hardness 7) and its lack of cleavage (it breaks in irregular, shell-like curves). Common in mountainous regions, riverbeds, and as veins in granite or metamorphic rocks.

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