mineral

Quartz (Iron-Stained Quartz Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Yellowish-tan to golden brown due to iron oxide staining; Luster: Vitreous to waxy (distinguishable after being river-worn); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Yellowish-tan to golden brown due to iron oxide staining
Luster: Vitreous to waxy (distinguishable after being river-worn)

Identified April 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or within igneous and metamorphic rocks. This specific specimen is a water-worn river pebble, shaped by alluvial erosion over thousands of years and stained by limonite or hematite infiltration.

Uses & applications

Used in industrial glassmaking, abrasives, and electronics. River pebbles are popular for landscaping, aquarium decor, and pocket stones for collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Specimens like this are often mistakenly called 'Gold Quartz' by amateurs because iron staining can mimic the appearance of gold veins to the untrained eye.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and stainless steel) and its lack of cleavage. Look for it in riverbeds, gravel pits, and mountain streams. Its smooth, rounded texture indicates significant transport from its source rock.

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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

Metamorphic Rock

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mineral