mineral

Quartz (Milky/Gray variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent gray to milky white with iron staining; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Translucent gray to milky white with iron staining
Luster: Vitreous (glassy) to greasy

Identified April 7, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. It is one of the most abundant minerals and can form in igneous, metamorphic, and sedimentary environments over billions of years.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), abrasives, and as a gemstone or decorative specimen.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities and inclusions create many varieties like amethyst, citrine, and this smoky/milky variety.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel) and its lack of cleavage, breaking instead into curved, shell-like surfaces. Found globally in almost all geological environments.