mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: Opaque white (milky)
Luster: Vitreous to greasy

Identified June 9, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in hydrothermal veins or pegmatites from silica-rich fluids. The 'milky' appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. Can be found in geological formations of almost any age.

Uses & applications

Used as a source of silicon for electronics, in landscaping, as an abrasive, and occasionally in jewelry as cabochons. Large clear pieces are popular for mineral collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Historically, milky quartz was used for stone tools when flint was unavailable. It is often a 'pathfinder' mineral for gold in quartz veins.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, and white opaque color. Common worldwide, often found in mountain ranges, stream beds, and beach gravel. Clear signal of post-magmatic activity.