mineral

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: whitish, semi-translucent to tan; Luster: vitreous to waxy; Crystal structure: Trigonal (often massive in rounded pebbles); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: whitish, semi-translucent to tan
Luster: vitreous to waxy

Identified July 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of magma or by hydrothermal precipitation in veins. These small, rounded pebbles are usually the result of long-term weathering and transport by water in stream beds or coastal environments.

Uses & applications

Used in glass manufacturing, electronics (piezoelectric properties), abrasives, and as decorative stone or landscaping gravel.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is clear, but impurities and microscopic fluid inclusions create the milky or tan appearance seen in this specimen.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage. It is found globally in riverbeds, beaches, and soil. Collectors look for unique inclusions or high clarity.