mineral

Quartz (Grain/Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: brownish-tan (likely stained by iron); Luster: vitreous (glassy) to waxy; Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: brownish-tan (likely stained by iron)
Luster: vitreous (glassy) to waxy

Identified June 3, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: brownish-tan (likely stained by iron); Luster: vitreous (glassy) to waxy; Crystal structure: Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed through the crystallization of molten magma or by precipitation from hydrothermal veins. This specific specimen appears to be a weathered detrital grain from a sedimentary environment like a riverbed or soil.

Uses & applications

While massive quartz is used in glassmaking and electronics, small pebbles like this are primarily used as landscape gravel or aggregate in construction. High-quality crystals are used in jewelry.

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 small grains after other minerals have eroded away.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and lack of cleavage. Common in almost all geological environments worldwide, especially in sandy soils and river deposits.