mineral

Milky Quartz with Matrix

Silicon Dioxide (SiO2)

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

Identified June 23, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal fluids in cracks or veins within other rocks. The bubbles of gas or liquid trapped during crystal growth give it the 'milky' appearance.

Uses & applications

Used in glassmaking, construction as aggregate, electronics (due to piezoelectric properties), and occasionally as a tumbling stone or gravel element in landscaping.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is specifically opaque because of microscopic fluid inclusions trapped since its formation.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its lack of cleavage, and its waxy/vitreous luster. Common in riverbeds, mountains, and as garden stones globally.