mineral
Ferruginous Quartz (Iron-Stained Quartz Pebble)
Silicon Dioxide with Iron Oxides (SiO2 + Fe2O3)
AI-generated identification · may be incorrectHardness of 7 on Mohs scale; greasy to vitreous luster; translucent to opaque with reddish-orange, brown, and clear/milky patches; conchoidal fracture with no cleavage; specific gravity around 2.65.
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Physical properties
Hardness of 7 on Mohs scale; greasy to vitreous luster; translucent to opaque with reddish-orange, brown, and clear/milky patches; conchoidal fracture with no cleavage; specific gravity around 2.65.
Formation & geological history
Formed initially in hydrothermal veins or pegmatites where silica crystallized, followed by exposure to iron-rich fluids causing hematite/limonite staining. It was later weathered and rounded by alluvial, river, or coastal wave action into a smooth pebble.
Uses & applications
Commonly tumbled and polished for decorative stones, lapidary cabochons, metaphysical crystals, and landscaping gravel.
Geological facts
Quartz is one of the most resistant minerals to both physical abrasion and chemical weathering, which is why quartz pebbles often survive long after surrounding host rocks have eroded away into soil or sand.
Field identification & locations
Identified in the field by its ability to scratch glass (hardness 7), vitreous to waxy luster, lack of cleavage, and patchy rust-red inclusions. Abundantly found in riverbeds, gravel bars, and glacial till across the world.
