mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: Cloudy white to opaque
Luster: Vitreous (glassy) to greasy

Identified March 31, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal solutions or cooling magma. The milky appearance is caused by microscopic inclusions of fluids (gas or liquid) trapped during crystal growth. It can be found in igneous, metamorphic, and sedimentary environments across all geological ages.

Uses & applications

Used in the production of glass, ceramics, and silicon for electronics. In the gemstone trade, it is used for beads, carvings, and tumbled stones. It is also a very common specimen for amateur geology collections.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of crystalline quartz. Historically, it has been used for stone tools due to its hardness and the sharp edges produced by its conchoidal fracture.

Field identification & locations

Identify in the field by its white color, ability to scratch glass (hardness 7), and lack of cleavage (it breaks in irregular, curved shards). Frequently found in hydrothermal veins, mountain regions, and as pebbles in riverbeds or beaches.