mineral

Quartz (Common or Milky)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Colorless to milky white/translucent tan, Luster: Vitreous/glassy to waxy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified June 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed from cooling silica-rich magma or from hydrothermal solutions in veins. This specimen appears water-worn or weathered, likely found in a riverbed or alluvial deposit. Quartz can form in almost any geological age.

Uses & applications

Used extensively in glassmaking, electronics (piezoelectric properties), abrasives, construction aggregates, and as gemstones in jewelry.

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 often remains as pebbles long after other minerals have eroded.

Field identification & locations

Identify in the field by its hardness (it will easily scratch glass and cannot be scratched by a steel knife) and its lack of cleavage. Found globally in almost all geological environments.