mineral

Quartz (Smoky/Milky variety)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Translucent grey to tan, Luster: Vitreous to greasy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific gravity: 2.65

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Translucent grey to tan, Luster: Vitreous to greasy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific gravity: 2.65

Formation & geological history

Forms in igneous rocks like granite or in hydrothermal veins. This specimen appears water-worn, likely from a fluvial (river) or coastal environment.

Uses & applications

Used in glass making, electronics (piezoelectric properties), abrasives, and as a semi-precious gemstone in jewelry and decor.

Geological facts

Quartz is one of the most abundant minerals in Earth's crust. It is highly resistant to chemical and physical weathering, which is why it often survives as rounded pebbles in gravel.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of cleavage. Found globally in almost all geological environments.