mineral
Tumbled amber-colored chalcedony (likely carnelian or yellow agate)
Microcrystalline quartz, SiO₂; likely iron-bearing chalcedony
AI-generated identification · may be incorrectHardness 6.5–7 Mohs; translucent honey-yellow to orange-brown, waxy to vitreous luster, cryptocrystalline quartz with no visible cleavage. The smooth, glossy surface indicates tumbling or polishing.
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Physical properties
Hardness 6.5–7 Mohs; translucent honey-yellow to orange-brown, waxy to vitreous luster, cryptocrystalline quartz with no visible cleavage. The smooth, glossy surface indicates tumbling or polishing.
Formation & geological history
Forms when silica-rich groundwater fills cavities and fractures, with iron impurities producing yellow, orange, or red coloration; commonly Cenozoic to older volcanic-hosted deposits.
Uses & applications
Used as a lapidary stone for cabochons, beads, carvings, and inexpensive jewelry; also collected as an ornamental gemstone.
Geological facts
Carnelian is typically orange-red, while yellow varieties are often sold as yellow agate or citrine-colored chalcedony. Heat treatment can intensify orange coloration.
Field identification & locations
Identify by its fine-grained, glassy/waxy appearance, lack of cleavage, and ability to scratch ordinary glass; chalcedony feels cooler and harder than plastic or resin. Common sources include Brazil, India, Uruguay, Madagascar, and the United States.
