Quartz (Milky/Smoky variety)

Physical Properties

Hardness: 7 on the Mohs scale; Color: Cloudy white to brownish-grey; Luster: Vitreous (glassy) to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed from the crystallization of silica-rich magma or precipitation from hydrothermal veins. It is found in all types of geological environments (igneous, metamorphic, and sedimentary) and can be hundreds of millions of years old.

Uses & Applications

Used extensively in electronics (piezoelectric properties), glassmaking, abrasives, jewelry (as semi-precious stones), and as a landscape/construction material.

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 ability to scratch glass, lack of cleavage, and glassy appearance. It is common worldwide, particularly in granite outcroppings and riverbeds.

Identified on: 4/17/2026

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