mineral

Milky Quartz

Milky Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: Opaque white to cloudy grey
Luster: Vitreous (glassy) to greasy

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. The milky appearance is caused by tiny fluid inclusions of gas and/or liquid trapped during crystal growth. Can be found in geological formations ranging from Precambrian to Cenozoic eras.

Uses & applications

Used in the glassmaking industry, as an abrasive, in the production of silicon for electronics, and as decorative aggregate in landscaping. It is also popular among crystal collectors and used in lapidary for carvings and cabochons.

Geological facts

Milky quartz is the most common variety of crystalline quartz. While often overlooked for clearer varieties like rock crystal, massive veins of milky quartz are sometimes associated with gold deposits, leading miners to refer to it as 'gold quartz'.

Field identification & locations

Identify in the field by its distinct white color, inability to be scratched by a steel knife (hardness test), and lack of cleavage planes. It is globally ubiquitous, found commonly in pegmatites, hydrothermal veins, and as pebbles in riverbeds.