mineral
Tumbled carnelian (orange chalcedony)
Chalcedony, microcrystalline quartz (SiO₂), colored by iron oxides
AI-generated identification · may be incorrectMohs hardness 6.5–7; orange, rust-red, and cream mottling with a polished, vitreous-to-waxy luster. Quartz’s trigonal crystal structure is microscopic; no visible cleavage and conchoidal fracture when broken.
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Physical properties
Mohs hardness 6.5–7; orange, rust-red, and cream mottling with a polished, vitreous-to-waxy luster. Quartz’s trigonal crystal structure is microscopic; no visible cleavage and conchoidal fracture when broken.
Formation & geological history
Silica-rich fluids deposit chalcedony in cavities and fractures, often in volcanic rocks; iron impurities produce its warm colors. Such deposits occur across many geological ages.
Uses & applications
Used for beads, cabochons, ornaments, and small carvings; this tumbled piece is primarily a decorative or collecting specimen.
Geological facts
Carnelian is a translucent to opaque variety of chalcedony; the pictured stone’s cream and gray areas suggest mixed chalcedony or other inclusions rather than uniformly colored carnelian.
Field identification & locations
Look for fine, non-granular texture, hardness near 7, and waxy luster; it is commonly found in volcanic geodes and alluvial gravels, including in India, Brazil, and Uruguay.
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