mineral

Quartz (White/Milky Pebble)

Silicon Dioxide (SiO2)

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

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

Identified March 7, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through the cooling of magma or precipitation from hydrothermal veins. This specific specimen is a water-worn river or beach pebble, smoothed over thousands of years by hydraulic action.

Uses & applications

Used in the manufacture of glass, ceramics, and abrasives. In construction, it is used as a component in concrete or as decorative landscaping stone. Smooth pebbles are popular for 'worry stones' and aquarium decor.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its white color from microscopic fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and lack of cleavage. Look for it in stream beds, gravel pits, and beaches globally. It is a 'marker' mineral for many prospectors.