mineral

Quartz Pebble (Quartzite / Smoky Quartz)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: translucent gray, brownish to whitish; Luster: vitreous (glassy) to greasy; Crystal Structure: trigonal/hexagonal; Cleavage: none (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: translucent gray, brownish to whitish
Luster: vitreous (glassy) to greasy

Identified July 26, 2026More mineral →

Explore Quartz Pebble (Quartzite / Smoky Quartz) in the encyclopedia →

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Physical properties

Formation & geological history

Formed through hydro-thermal vein deposition or metamorphism of quartz sandstone (quartzite), followed by alluvial weathering and stream or beach erosion rounding.

Uses & applications

Used in glass manufacturing, electronics (silicon source), landscaping, construction aggregate, and as tumbling rough for lapidary enthusiasts.

Geological facts

Quartz is one of the most abundant minerals in Earth's continental crust. Rounded river or beach pebbles like this specimen often feature small sand or salt grains clinging to their surface when collected near shores.

Field identification & locations

Identified by its high hardness (scratches glass, cannot be scratched by a steel knife), lack of cleavage, and greasy-to-glassy fracture surface. Commonly found along riverbeds, beaches, and gravel deposits worldwide.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Limonite / Goethite (Iron Ore Mineral nodule)

FeO(OH)·nH2O / FeO(OH)

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Schist

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Septarian Pebble

Septarian nodule / Concretion

sedimentary

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

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Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary