mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale; Color: White to opaque (milky); Luster: Vitreous to greasy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on the Mohs scale
Color: White to opaque (milky)
Luster: Vitreous to greasy

Identified March 20, 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 the Mohs scale; Color: White to opaque (milky); Luster: Vitreous 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 from hydrothermal veins. It can be found in a wide variety of geological environments ranging from igneous to metamorphic and sedimentary rocks through Earth's history.

Uses & applications

Used in the manufacturing of glass, ceramics, and abrasives. High-purity quartz is essential in electronics (semiconductors) and watches (quartz oscillators). Occasionally used in construction and for decorative landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The 'milky' appearance is caused by tiny fluid inclusions of gas or liquid trapped during crystal growth. It is chemically very stable and resistant to weathering.

Field identification & locations

Identify in the field by its ability to scratch glass, lack of cleavage, and white opaque color. It is commonly found in gravel beds, mountain ranges, and near pegmatite veins. Collectors look for well-formed crystal points, though milky quartz is often found as massive lumps.