Quartz (Milky/Smoky variety)

Physical Properties

Hardness: 7 on Mohs scale; Color: Cloudy white to translucent grey; Luster: Vitreous/Glassy; 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 almost all geological environments and across all ages of Earth's history.

Uses & Applications

Used widely in glassmaking, electronics (piezoelectric properties), abrasives, and as a semi-precious gemstone in jewelry and decorative carvings.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to both chemical and physical weathering, which is why it is the primary component of most beach sand.

Field Identification & Locations

Identify in the field by its inability to be scratched by a steel knife (H=7), its lack of cleavage, and its characteristic waxy or glassy luster. Commonly found in riverbeds, mountains, and outcroppings worldwide.

Identified on: 4/22/2026

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