Quartz (Common Milky Quartz)

Physical Properties

Hardness: 7 on Mohs scale; Color: Translucent white to light gray; Luster: Vitreous (glassy) to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & Geological History

Formed in a wide variety of environments, most commonly by the cooling of silica-rich magma or through hydrothermal activity in veins. It is found in igneous, metamorphic, and sedimentary rocks throughout all geological periods.

Uses & Applications

Used in glass manufacturing, electronics (due to piezoelectric properties), construction as an abrasive, and lower-grade specimens are common in the rock tumbling and collecting hobby.

Geological Facts

Quartz is the second most abundant mineral in Earth's continental crust. It was historically used to make stone tools due to its hardness and the way it fractures into sharp edges.

Field Identification & Locations

Identify by its inability to be scratched by a steel knife and its lack of cleavage planes. Found globally in almost every geological setting, including mountain ranges, riverbeds, and beaches.

Identified on: 5/18/2026

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