mineral

Milky Quartz

Silicon Dioxide (SiO2)

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

Hardness: 7 on the Mohs scale
Color: Opaque white
Luster: Vitreous to greasy

Identified March 15, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from the cooling of silica-rich hydrothermal fluids in veins or within igneous pegmatites. The white 'milky' appearance is caused by microscopic fluid inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used widely in glass making, ceramics, as an abrasive, in the production of silicon for electronics, and as decorative landscape stone or gravel.

Geological facts

Quartz is the second most abundant mineral in the Earth's continental crust. Ancient Greeks named the mineral 'krystallos,' believing it 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/steel), lack of cleavage, and white opaque color. It is extremely common in riverbeds, mountains, and gravel pits worldwide.