mineral

Quartz (specifically a water-worn Quartzite or Chalcedony pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Tan, brown, or translucent beige; Luster: Waxy to vitreous; Crystal Structure: Trigonal (often microcrystalline as chalcedony or massive in quartzite); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Tan, brown, or translucent beige
Luster: Waxy to vitreous

Identified May 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the crystallization of silica-rich fluids or the metamorphism of sandstone. This specific specimen has been significantly eroded and smoothed by mechanical action in water (river or beach environment).

Uses & applications

Raw quartz is used in glass making, abrasive manufacturing, electronics (due to piezoelectricity), and as a gemstone when high quality. Tumbled pebbles are common in landscaping and decorative aquariums.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Specimens found as smooth pebbles have often traveled miles from their original source via riverbeds or glacial movement.

Field identification & locations

Identify in the field by its inability to be scratched by a steel pocketknife and its lack of visible layers. Look for it along river banks, shorelines, or gravel pits worldwide.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

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

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic

Green Apatite on Albite

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

mineral