mineral

Quartz vein fragments on Sandstone cobble

SiO2 (Silicon Dioxide)

Hardness: 7 on Mohs scale; Color: Milky white to clear translucent fragments resting on a light brown/grey ground rock; Luster: Vitreous to greasy; Fracture: Conchoidal; Crystal structure: Trigonal/Hexagonal

Hardness: 7 on Mohs scale
Luster: Vitreous to greasy

Identified July 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed via hydrothermal precipitation in rock fractures, where silica-rich fluids cooled and crystallized over deep geological time. Later eroded and broken into vein quartz pebbles alongside fine-grained sedimentary alluvial sandstone pebbles. Found in the Caucasus region near Dagestan (41.5°N, 47.7°E).

Uses & applications

Quartz is widely used in electronics, optics, glassmaking, and abrasive production. Common specimens serve decorative and educational purposes in collections.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its high hardness (7) allows it to survive heavy stream erosion and transportation long after surrounding softer host rocks have weathered away.

Field identification & locations

Can be identified by its ability to easily scratch glass and steel, milky white appearance, vitreous luster, lack of cleavage, and sharp conchoidal fracture edges. Extremely common in river beds and alluvial gravel deposits worldwide.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Sandstone with Mineral Veining or Crust

Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)

sedimentary

Potassium Feldspar (Orthoclase)

Orthoclase (KAlSi3O8)

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Gypsum (variety Selenite or Alabaster)

Calcium sulfate dihydrate (CaSO4·2H2O)

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Nephrite

Mineral/Rock