mineral
Quartz (Chalcedony / Rough Quartz Pebble)
Silicon Dioxide (SiO2)
Hardness of 7 on Mohs scale, translucent to sub-translucent waxy to vitreous luster, colorless to brownish-beige tint, conchoidal fracture, trigonal crystal system, specific gravity around 2.65.
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Physical properties
Hardness of 7 on Mohs scale, translucent to sub-translucent waxy to vitreous luster, colorless to brownish-beige tint, conchoidal fracture, trigonal crystal system, specific gravity around 2.65.
Formation & geological history
Formed through precipitation from silica-rich fluids in cavities, veins, or as weathered pebbles in sedimentary gravel beds and alluvial deposits.
Uses & applications
Used in lapidary arts, jewelry (tumbling and cabochon cutting), industrial abrasives, and popular among amateur rock collectors.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Chalcedony forms from microscopic intergrowths of quartz and moganite.
Field identification & locations
Identify by its hardness (scratches glass), lack of distinct cleavage, smooth or conchoidal fracture surfaces, and translucent quality. Commonly found in riverbeds, beach gravels, and exposed rock veins worldwide.
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