mineral

Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Tan to milky white; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: Tan to milky white
Luster: Vitreous to greasy

Identified June 25, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Tan to milky white; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture).

Formation & geological history

Forms in a wide variety of environments, primarily through the cooling of silica-rich magma or precipitation from hydrothermal veins. Often found as rounded pebbles in fluvial (river) deposits.

Uses & applications

Widely used in glassmaking, electronics (oscillators), construction as an abrasive, and lower-grade specimens are common for landscape decoration.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is chemically very stable and resistant to weathering, which is why it often remains as pebbles after other minerals have eroded.

Field identification & locations

Identified in the field by its hardness (it will scratch glass) and lack of cleavage. These specimens appear to be iron-stained quartz pebbles common in riverbeds.