mineral

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to tan with iron staining; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Milky white to tan with iron staining
Luster: Vitreous to waxy

Identified March 27, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white to tan with iron staining; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed through hydrothermal processes, crystallization from cooling magma, or precipitation from silica-rich fluids. This specimen appears water-worn or tumbled, likely sourced from a fluvial (river) or alluvial deposit.

Uses & applications

Used widely in glassmaking, abrasives, and as a component in concrete. In electronics, it's used for its piezoelectric properties. This specific grade is mostly for landscaping or casual collecting.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to chemical and physical weathering, which is why it often remains as rounded pebbles in riverbeds.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (H=5.5) and its lack of cleavage. It is found globally in almost all geological environments, particularly in gravel pits and beaches.