mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to opaque; Luster: Vitreous to greasy; Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to opaque
Luster: Vitreous to greasy

Identified May 25, 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: Milky white to opaque; Luster: Vitreous to greasy; Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms from the cooling of silica-rich hydrothermal fluids in veins or as the final crystallization product in igneous pegmatites. It is found in a wide range of geological environments, including metamorphic and sedimentary rocks, and can be billions of years old.

Uses & applications

Used primarily in construction as aggregate, in glassmaking, as an abrasive, and as a semi-precious gemstone in jewelry or for decorative ornamental carvings.

Geological facts

The milky appearance is caused by tiny inclusions of gas and liquid trapped during the crystal's formation. It is one of the most abundant minerals in the Earth's crust.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, and white opaque appearance. For collectors, look in riverbeds or near mountain outcrops. It is commonly used as a 'pathfinder' mineral for gold veins.