mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to opaque; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to opaque
Luster: Vitreous to waxy

Identified July 21, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white to opaque; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed from silica-rich hydrothermal fluids or through the cooling of magma in igneous rocks like pegmatites. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. This specimen has been rounded by water erosion in a river or beach environment.

Uses & applications

Used as decorative landscaping stone, in glass manufacturing, as a source of silicon for electronics, and in various spiritual practices.

Geological facts

Milk quartz is the most common variety of crystalline quartz found on Earth. Its white color is due to microscopic fluid inclusions that occurred during the crystal's formation millions of years ago.

Field identification & locations

Identified by its white color, inability to be scratched by steel, and its smooth, water-worn texture. It is ubiquitous in gravel beds, stream deposits, and glacial till worldwide.