mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white to creamy; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

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

Identified March 7, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white to creamy; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed through the crystallization of molten magma or from hydrothermal veins. Milky quartz gets its cloudy appearance from minute fluid inclusions of gas or liquid trapped during crystal growth. It can be found in geological environments ranging from Precambrian to Cenozoic eras.

Uses & applications

Used in the production of glass and ceramics, as an abrasive in sandblasting, in the manufacturing of silicon chips (semiconductors), for landscaping/construction gravel, and as a popular specimen for beginner rock collectors.

Geological facts

Milky quartz is the most common variety of crystalline quartz. The 'milkiness' is caused by millions of tiny bubbles of water or CO2 that scatter light. Historically, quartz was believed by ancient Greeks to be ice that had frozen so hard it would never melt.

Field identification & locations

Identify in the field by its ability to scratch glass (hardness 7), its lack of cleavage, and its common occurrence in veins within granite or metamorphic rocks. It is found worldwide, with major deposits in the USA, Brazil, and Madagascar.