mineral

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent; Luster: Vitreous to waxy (when river-worn); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to translucent
Luster: Vitreous to waxy (when river-worn)

Identified July 8, 2026More mineral →

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Physical properties

Formation & geological history

Forms from the crystallization of molten magma or from hydrothermal veins. This specific specimen appears to be a river-worn or water-eroded pebble, acquiring its rounded shape through mechanical weathering over thousands of years.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), abrasives, and as decorative gravel or gemstones.

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 by its hardness (it will scratch glass) and lack of cleavage. Commonly found in riverbeds, beaches, and mountain trails globally. It is a staple for beginner rockhounds.