mineral
Tumbled carnelian
Carnelian, orange-red chalcedony (microcrystalline SiO₂)
AI-generated identification · may be incorrectHardness 6.5–7 Mohs; translucent orange, red, and brown with a waxy to vitreous luster. Its microscopic quartz crystals form a compact, cryptocrystalline structure with no visible cleavage; the polished surface shows natural-looking color bands or cloudy zones.
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Physical properties
Hardness 6.5–7 Mohs; translucent orange, red, and brown with a waxy to vitreous luster. Its microscopic quartz crystals form a compact, cryptocrystalline structure with no visible cleavage; the polished surface shows natural-looking color bands or cloudy zones.
Formation & geological history
Forms as silica-rich chalcedony in cavities and veins, commonly in volcanic rocks; iron impurities produce its warm colors. It occurs in rocks of many ages, and this specimen has been tumbled and polished.
Uses & applications
Used for beads, cabochons, carvings, and ornamental objects; historically valued for seals and jewelry.
Geological facts
Carnelian is a variety of chalcedony, itself a microcrystalline form of quartz. Heat treatment can intensify or alter its color.
Field identification & locations
Common sources include India, Brazil, Uruguay, and Madagascar. Look for translucency, orange-to-red color, and hardness near quartz; the image shows a polished specimen, so field identification is limited.
