mineral

Quartz (Milky Quartz)

Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: Opaque white to light gray
Luster: Vitreous to greasy

Identified June 20, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed primarily from hydrothermal veins and cooling magma, as well as in metamorphic and sedimentary environments. Quartz is one of the most abundant minerals in the Earth's crust.

Uses & applications

Used in glass manufacturing, electronics (due to its piezoelectric properties), abrasives, and as a component in building materials like concrete. Lower quality specimens are common in landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities create various colors like amethyst, citrine, and as seen here, milky quartz due to fluid inclusions.

Field identification & locations

Identify in the field by its hardness (it can scratch glass and steel) and lack of cleavage. It is found globally in almost all rock environments. To collectors, this specific specimen appears to be a common river-worn or weathered quartz pebble.

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Mineral/Rock

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Metamorphic Rock

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mineral