Milky Quartz

Physical Properties

Hardness: 7 (Mohs scale); Color: White, translucent to opaque; 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 precipitation from hydrothermal veins. The milky appearance is caused by tiny liquid or gas inclusions trapped during crystal growth.

Uses & Applications

Used in the production of glass, ceramics, and abrasives; also used for landscaping, as a gemstone (cabochons), and in electronics for its piezoelectric properties.

Geological Facts

Milky Quartz is the most common variety of crystalline quartz. While most colored varieties like Amethyst get their color from chemical impurities, Milky Quartz gets its color from structural flaws—specifically microscopic bubbles of fluid.

Field Identification & Locations

Identify by its ability to scratch glass, its milky white appearance, and lack of cleavage (it breaks in curved, shell-like patterns). It is ubiquitous worldwide in igneous, metamorphic, and sedimentary environments.

Identified on: 4/18/2026

Mode: Standard