mineral

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: White to translucent
Luster: Vitreous (glassy) to greasy

Identified March 25, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. It can be found in igneous, metamorphic, and sedimentary environments globally, often billions of years old in ancient cratons.

Uses & applications

Used in glassmaking, abrasives, electronics (piezoelectric properties), construction (aggregate), and common gemstone jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities or fluid inclusions create varieties like Milky Quartz, Amethyst, and Citrine.

Field identification & locations

Identify in the field by its hardness (will scratch glass), lack of cleavage, and translucent appearance. Found virtually everywhere on Earth, often in riverbeds or mountain ranges.