mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Milky white to off-white. 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 off-white
Luster: Vitreous to waxy

Identified July 22, 2026More mineral →

Explore Milky Quartz Pebble in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale. Color: Milky white to off-white. Luster: Vitreous to waxy. Crystal Structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Formation & geological history

Formed in hydrothermal veins and igneous intrusions where silica-rich fluids crystallized slowly. Milky appearance is caused by microscopic fluid inclusions trapped during growth. Smooth shape is due to natural stream, river, or ocean erosion.

Uses & applications

Used in landscaping, decorative rock gardens, aquariums, tumbling/polishing projects, and occasionally as a source of silicon in industrial processes.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its opaque white color from millions of tiny trapped bubbles of gas or liquid formed during its growth.

Field identification & locations

Can be identified in the field by its hardness (scratches glass easily, cannot be scratched by steel), smooth river-worn shape, and characteristic milky white translucent body. Commonly found in riverbeds, beaches, and gravel pits worldwide.