mineral
Carnelian
SiO2 (Silicon Dioxide - Chalcedony variant)
Hardness 6.5-7 on Mohs scale, reddish-orange to brownish-red color, waxy to vitreous luster, trigonal microcrystalline structure, conchoidal fracture, no cleavage, specific gravity ~2.58-2.64.
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Physical properties
Hardness 6.5-7 on Mohs scale, reddish-orange to brownish-red color, waxy to vitreous luster, trigonal microcrystalline structure, conchoidal fracture, no cleavage, specific gravity ~2.58-2.64.
Formation & geological history
Forms in low-temperature hydrothermal environments and silica-rich solution deposits within volcanic rock cavities, basalt gas bubbles, and sedimentary deposits.
Uses & applications
Widely used for lapidary work, cabochons, carved gemstones, beads, tumbled pocket stones, and decorative jewelry.
Geological facts
Carnelian has been used for jewelry and seal rings for over 4,500 years. Ancient Romans used carnelian signet rings to seal wax documents because hot wax does not stick to it.
Field identification & locations
Identified by its warm translucent reddish-orange to brownish color, smooth waxy polish, and high hardness (scratches glass). Commonly found in Brazil, India, Madagascar, Uruguay, and parts of the USA.
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