mineral

Quartz (Milky or Grainy Variety)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Translucent to opaque white/yellowish; Luster: Vitreous to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Translucent to opaque white/yellowish
Luster: Vitreous to greasy

Identified March 20, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Translucent to opaque white/yellowish; Luster: Vitreous to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & geological history

Formed from the crystallization of silica-rich magma or precipitation from hydrothermal fluids. Geologically omnipresent, appearing in igneous, metamorphic, and sedimentary rocks of nearly all ages.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), construction as an aggregate, and in jewelry as semi-precious gemstones or beads.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ancient Greeks believed quartz was ice that had frozen so hard it would never melt.

Field identification & locations

Identify in the field by its ability to scratch glass and lack of cleavage. Commonly found in riverbeds, mountains, and beaches worldwide. Collectors look for well-defined hexagonal crystal points.