mineral

Milk Quartz (River Pebble)

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Milky white with orange iron-oxide staining; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white with orange iron-oxide staining
Luster: Vitreous to greasy

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal fluids in veins or as a primary mineral in igneous rocks. This specimen is a 'water-worn' pebble, meaning its rounded shape was created by mechanical erosion in a high-energy aquatic environment like a river or beach over hundreds to thousands of years.

Uses & applications

Massively used in glassmaking and abrasives. In this smoothed form, it is often used for decorative landscaping, aquarium gravel, or as pocket stones for 'crystal healing' enthusiasts.

Geological facts

Milky quartz gets its white, opaque appearance from microscopic fluid inclusions of gas or liquid trapped during the crystal's growth. It is the most common variety of crystalline quartz on Earth's crust.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of cleavage planes. It is found globally in riverbeds, glacial tills, and beaches. Collectors should look for unique internal fractures or 'phantom' inclusions.

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