mineral

Quartz (Milky/Cloudy Variety)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: translucent white to milky; Luster: Vitreous/Glassy; Crystal structure: Trigonal (Hexagonal system); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: translucent white to milky
Luster: Vitreous/Glassy

Identified January 24, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: translucent white to milky; Luster: Vitreous/Glassy; Crystal structure: Trigonal (Hexagonal system); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Formation & geological history

Forms in igneous, metamorphic, and sedimentary environments. Most commonly crystallizes from cooling magma or hydrothermal veins. This smooth, rounded specimen (pebble) was likely formed by water erosion in a river or stream bed over hundreds to thousands of years.

Uses & applications

Used in glassmaking, abrasives, and the electronics industry (due to piezoelectric properties). Smaller pebbles are used for landscaping, construction aggregates, and as gemstones for tumble-polishing.

Geological facts

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

Field identification & locations

Identify by its hardness (it will scratch glass and steel) and lack of cleavage. Found globally in river sediments, beaches, and mountainous outcrops. Collectors should look for the characteristic waxy to glassy sheen and rounded edges in water-transported areas.

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