mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: White to translucent; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: White to translucent
Luster: Vitreous to greasy

Identified March 16, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: White to translucent; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Forms in igneous, metamorphic, and sedimentary environments. Most commonly originates from hydrothermal veins or as a primary constituent in granite. The milky appearance is caused by tiny fluid inclusions of gas and/or liquid trapped during crystal growth.

Uses & applications

Used in the manufacturing of glass, ceramics, and abrasives. Large quantities are used in the construction industry as aggregate. Lower quality specimens are used for landscaping or as decorative garden stones.

Geological facts

Milky quartz is the most common variety of crystalline quartz. While it lacks the clarity of rock crystal, it is chemically identical. It is often found as 'river stones' due to its extreme durability and resistance to weathering.

Field identification & locations

Identify in the field by its ability to scratch glass (hardness test) and its lack of cleavage planes. It is found globally, very commonly in riverbeds, glacial deposits, and mountain ranges. Collectors look for pieces with interesting shapes or banding.