mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white to cream; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified July 7, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white to cream; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed from silica-rich hydrothermal solutions in veins or as a primary constituent of igneous and metamorphic rocks. This specimen likely originates from the Sierra Nevada foothills context consistent with the 38.5°N, 121.5°W coordinates (Sacramento/Gold Country area).

Uses & applications

Used as an abrasive, in glass manufacturing, as a gemstone (low value), and as an indicator for gold prospectors.

Geological facts

Milky quartz gets its cloudy appearance from minute fluid inclusions of gas or liquid trapped during the crystal's growth. It is the most common variety of crystalline quartz.

Field identification & locations

Identify by its ability to scratch glass (Hardness 7), lack of cleavage, and white opaque color. In the provided Northern California location, it is a common sight in riverbeds and as float near quartz veins often associated with the Mother Lode.