mineral
Carnelian (Tumbled)
Silicon Dioxide (SiO2)
Hardness 6.5-7 on Mohs scale; reddish-orange to brownish-red color; vitreous to waxy luster; microcrystalline/trigonal structure; no cleavage; Conchoidal fracture; 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; vitreous to waxy luster; microcrystalline/trigonal structure; no cleavage; Conchoidal fracture; specific gravity 2.58-2.64.
Formation & geological history
Formed as silica-rich fluids deposit in gas cavities (vesicles) within volcanic basaltic or metamorphic rocks. The distinct red-orange hue is caused by iron oxide impurities.
Uses & applications
Popular in jewelry, beads, cabochons, carved seals, and lapidary crafts; widely collected as a tumbled crystal.
Geological facts
Carnelian has been used for over 4,500 years; ancient Romans and Egyptians used it in signet rings and amulets to signify power and protection.
Field identification & locations
Look for a smooth, translucent to semi-translucent body with warm orange-red coloration and no sharp crystalline faces when tumbled. Found extensively in India, Brazil, Madagascar, and Uruguay.
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