mineral

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

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

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

Identified March 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich hydrothermal veins or within igneous pegmatites. The 'milky' appearance is caused by microscopic fluid inclusions of gas or liquid trapped during crystal growth. This specific specimen has been smoothed by fluvial or alluvial erosion.

Uses & applications

Milky quartz is used in the manufacture of glass, ceramics, and abrasives. In construction, it is used as decorative aggregate or landscape stone. Lower-quality specimens are common in 'rock tumbling' hobbies.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is often found alongside gold in hydrothermal veins, leading prospectors to use it as an indicator mineral for precious metals.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage. It is commonly found in riverbeds, beaches, and gravel pits across the globe. For collectors, look for pieces with crystalline terminations or interesting inclusions.