mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness 7 on the Mohs scale, milky white or translucent off-white color, vitreous to greasy luster, trigonal crystal system, conchoidal fracture, lack of cleavage, specific gravity of 2.65.

Identified July 26, 2026More mineral →

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Physical properties

Hardness 7 on the Mohs scale, milky white or translucent off-white color, vitreous to greasy luster, trigonal crystal system, conchoidal fracture, lack of cleavage, specific gravity of 2.65.

Formation & geological history

Forms in hydrothermal veins and igneous pegmatites through the cooling of silica-rich fluids. The characteristic milky appearance is caused by microscopic fluid or gas inclusions trapped within the crystal structure during growth.

Uses & applications

Widely used in lapidary work, jewelry, tumbling, landscaping, quartz glass manufacturing, optics, and electronics (due to its piezoelectric properties).

Geological facts

Milky quartz is one of the most common quartz varieties on Earth. The milky appearance is created by tiny bubble inclusions of liquids and gases trapped during its growth millions of years ago.

Field identification & locations

Identified by its harness (scratches glass), lack of cleavage, waxy to greasy luster, and milky white coloration. Found abundantly worldwide in riverbeds, mountains, and quartz vein outcrops.