sedimentary

Quartz Grain / Sandstone Fragment

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: tan to translucent brownish-orange (likely due to iron staining), Luster: vitreous to dull, Crystal structure: Hexagonal/Trigonal (though water-worn), Cleavage: None (conchoidal fracture).

Identified July 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the weathering and erosion of igneous rocks like granite. This specific grain appears to be a clastic sedimentary fragment, likely transported by water or wind until it reached its current rounded or sub-angular state.

Uses & applications

Primary component in construction (concrete/mortar), glass manufacturing, hydraulic fracturing (proppants), and filtration systems.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its high chemical and physical stability allows it to survive long-term erosion, eventually forming vast desert dunes and ocean beaches.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of reaction to acid. Commonly found in riverbeds, beaches, and soil worldwide. Look for a translucent 'glassy' appearance on fresh surfaces.

Other sedimentary specimens

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Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Cone-in-cone structure (Limestone)

Cone-in-cone structure (Secondary Sedimentary Structure)

sedimentary

Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

sedimentary

Chert Breccia

Brecciated Chert (Microcrystalline Silica)

sedimentary

Shale or Slaty Mudstone

Argillaceous sedimentary rock

sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary