mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, milky, or translucent; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White, milky, or translucent
Luster: Vitreous to greasy

Identified July 15, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White, milky, or translucent; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in hydrothermal veins or as a primary constituent of igneous rocks like granite. The milky appearance is caused by tiny inclusions of gas or liquid 'bubbles' trapped during crystal growth over millions of years.

Uses & applications

Used in glassmaking, as an abrasive, in the production of silicon wafers for electronics, and widely as decorative gravel or landscaping stone. High-quality pieces are used in jewelry and lapidary art.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is specifically characterized by its 'milky' white opacity caused by microscopic fluid inclusions.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), lack of cleavage, and white color. It is extremely common worldwide in riverbeds, mountains, and beaches.