mineral

Quartz (Milky or Cloudy Quartz)

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: Translucent white to milky
Luster: Vitreous (glassy) to greasy

Identified March 19, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Translucent white to milky; 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. The milky appearance is caused by tiny liquid or gas inclusions trapped during crystal growth. Can be found in geological formations ranging from billions of years old to relatively recent deposits.

Uses & applications

Used extensively in glassmaking, abrasives, foundry sand, and as a component in concrete. In higher quality forms, it is used in jewelry, electronics (piezoelectric properties), and as collector specimens.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz is the most common variety of quartz. Chemically, it is very stable and resistant to weathering, which is why it often persists as pebbles in riverbeds and beaches.

Field identification & locations

Identify by its ability to scratch glass (hardness 7), lack of cleavage, and waxy/glassy appearance. It is found globally in igneous, metamorphic, and sedimentary environments. Collectors look for unique shapes or clarity.

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