mineral

Milky Quartz

Crystalline Silicon Dioxide (SiO2)

Mohs hardness of 7, white or cloudy appearance, vitreous to greasy luster, trigonal crystal system (though often massive here), no cleavage, conchoidal fracture, specific gravity of 2.65.

Identified June 24, 2026More mineral →

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Physical properties

Mohs hardness of 7, white or cloudy appearance, vitreous to greasy luster, trigonal crystal system (though often massive here), no cleavage, conchoidal fracture, specific gravity of 2.65.

Formation & geological history

Formed during the late stages of hydrothermal activity and magma cooling. The milky appearance is caused by tiny inclusion of gas or liquid (fluid inclusions) trapped during the crystal's formation over millions of years.

Uses & applications

Used in glass manufacture, electronics (as a source of silicon), abrasives, and as decorative stone or landscaping material. High-quality specimens are used in healing crystals and jewelry.

Geological facts

Milky quartz is the most common variety of crystalline quartz. While it lacks the transparency of clear quartz, it is chemically identical. Large veins of it can often carry valuable precious metals like gold.

Field identification & locations

Identified by its white color, inability to be scratched by steel, and waxy surface when weathered. It is extremely common in riverbeds, mountain veins, and as cobbles in glacial till across the globe.