mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: White to opaque/cloudy; Luster: Vitreous (glassy) to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: White to opaque/cloudy
Luster: Vitreous (glassy) to greasy

Identified February 22, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to opaque/cloudy; Luster: Vitreous (glassy) 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 from hydrothermal veins. The milky appearance is caused by tiny fluid inclusions of gas or liquid trapped during crystal growth. They are found in igneous, metamorphic, and sedimentary environments globally.

Uses & applications

Used in glassmaking, abrasives, and as a source of silicon for electronics. In the gemstone trade, it is used for carvings, beads, and decorative landscaping. It also has historical use in making tools and weapons.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of quartz. Highly pure quartz is essential for the production of silicon chips used in computers and smartphones.

Field identification & locations

Identify in the field by its ability to scratch glass, its lack of cleavage, and its characteristic greasy-glassy luster. It is commonly found in gravel pits, mountain ranges, and as veins in other rocks. Collectors look for well-defined crystal points.