mineral

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

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

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

Identified March 25, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

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

Formation & geological history

Formed through the cooling of silica-rich magma or precipitation from hydrothermal veins. It is found in all geological environments and can be from any geological age (Archaean to Quaternary).

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), abrasives, construction as an aggregate, and for lapidary work in jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which originally meant 'hard'. Ancient Greeks believed quartz was ice that had frozen so hard it would never melt.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel), lack of cleavage, and white/cloudy appearance. Commonly found in riverbeds, mountains, and gravel pits worldwide.