mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

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

Hardness: 7 on the Mohs scale
Color: Opaque white to creamy tan
Luster: Vitreous to greasy

Identified March 21, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from the cooling of silica-rich magma or through hydrothermal activity where fluids crystallize in rock fractures. Extremely durable and resistant to chemical weathering, allowing it to survive as river or beach cobbles for millions of years.

Uses & applications

Used in glassmaking, abrasives, and as a component in concrete. In lapidary, it is used for tumbled stones, carvings, and bead jewelry. High-purity quartz is essential for electronic components and oscillators.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its white 'milky' appearance is caused by tiny inclusions of gas or liquid trapped during the crystal's growth.

Field identification & locations

Identify in the field by its hardness (it should scratch glass easily) and lack of cleavage. Commonly found in riverbeds, beaches, and gravel pits globally. To collectors, smooth river-worn specimens are great for rock tumbling.