mineral

Quartz (Microcrystalline variety)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: tan to milky white, Luster: Vitreous to waxy when wet, Crystal Structure: Trigonal (often massive in this form), Specific Gravity: 2.65

Identified June 18, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: tan to milky white, Luster: Vitreous to waxy when wet, Crystal Structure: Trigonal (often massive in this form), Specific Gravity: 2.65

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal solutions in voids of other rocks. Can be found in almost all geological environments and ages.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative gravel or gemstones.

Geological facts

Quartz is one of the most abundant minerals in Earth's crust. It is highly resistant to chemical and physical weathering, which is why it is commonly found as pebbles in riverbeds.

Field identification & locations

Identify by its ability to scratch glass and lack of cleavage. Commonly found in riverbeds, mountains, and beaches worldwide. This specific specimen appears to be a water-worn quartz pebble.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral