mineral

Milky Quartz Pebble (Tumbled Quartzite)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Opaque white to milky white. Luster: Vitreous to greasy. Crystal Structure: Hexagonal (trigonal), though typically massive in rounded pebbles. Cleavage: Indistinct/None (Conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Opaque white to milky white
Luster: Vitreous to greasy

Identified March 18, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or within pegmatites. The milky appearance is caused by microscopic inclusions of gas or liquids trapped during crystal growth. These pebbles are typically weathered from veins and rounded by water transport in rivers or oceans over thousands of years.

Uses & applications

Used in landscaping, as abrasive media, in glass manufacturing, and for decorative 'worry stones' or craft jewelry. High-purity quartz is also essential for silicon semiconductors and watch oscillators.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz specifically gets its color from tiny bubbles of carbon dioxide or water, creating a 'cloud' effect throughout the specimen.

Field identification & locations

Identify by its ability to scratch glass and lack of cleavage planes. Found globally in riverbeds, beaches, and mountain trails. It is a staple for beginner collectors because of its durability and ubiquitous nature.

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