mineral
Tumbled orange chalcedony or carnelian
Microcrystalline quartz (SiO₂), commonly iron-stained chalcedony; likely carnelian
AI-generated identification · may be incorrectOrange-red, translucent to semi-translucent, waxy to glassy luster, and cryptocrystalline structure with no visible cleavage; Mohs hardness 6.5–7 and specific gravity about 2.6. The rounded shape indicates tumbling or polishing.
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Physical properties
Orange-red, translucent to semi-translucent, waxy to glassy luster, and cryptocrystalline structure with no visible cleavage; Mohs hardness 6.5–7 and specific gravity about 2.6. The rounded shape indicates tumbling or polishing.
Formation & geological history
Forms when silica-rich groundwater fills cavities and fractures, with iron oxides producing orange-red coloration; deposits range from volcanic-hosted cavities to sedimentary veins, generally formed during relatively recent geologic episodes. Exact age cannot be determined from the image.
Uses & applications
Used for beads, cabochons, carvings, and inexpensive jewelry; also collected as a decorative gemstone. It has no major structural or industrial use beyond quartz aggregate.
Geological facts
Carnelian is an orange-red variety of chalcedony, while paler material may be called orange chalcedony. Color can deepen with heating or dyeing, and natural banding may be subtle or absent.
Field identification & locations
Identify by its even orange-red color, translucency, waxy surface, very high scratch resistance, and lack of cleavage; glass may show bubbles and scratches more easily. Common sources include India, Brazil, Uruguay, Madagascar, and parts of the United States.
