mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: Opaque white (milky)
Luster: Vitreous (glassy) to greasy

Identified March 20, 2026More mineral →

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Physical properties

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

Formation & geological history

Forms in igneous, metamorphic, and sedimentary environments. Milky quartz specifically occurs when gas or liquid bubbles are trapped during crystal formation. It is found in hydrothermal veins and pegmatites across all geological ages.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), abrasives, construction aggregates, and as decorative gemstones or carvings in jewelry.

Geological facts

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

Field identification & locations

Identify in the field by its ability to scratch glass, its lack of cleavage, and its characteristic waxy or glassy luster. Common in mountainous regions and riverbeds globally. It will not react with acid, unlike calcite.