gemstone

Orange chalcedony (likely carnelian)

Microcrystalline quartz, SiO₂; iron-bearing chalcedony (carnelian)

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange to reddish-orange, waxy to vitreous luster, cryptocrystalline structure, and no visible cleavage. The rough piece has a naturally irregular, partly conchoidal fracture.

Identified August 9, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron oxides producing the orange color; deposits range from ancient volcanic-hosted veins to younger sedimentary gravels. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.

Uses & applications

Used for cabochons, beads, carvings, ornamental objects, and lapidary specimens; durable but generally modestly priced.

Geological facts

Carnelian is the orange-red variety of chalcedony, while paler orange material may be called orange chalcedony. Color can be enhanced by heating or dyeing, so untreated status affects value.

Field identification & locations

Identify by its waxy luster, translucency, lack of cleavage, and ability to scratch glass; quartz crystal faces are absent because it is microcrystalline. This specimen could also be orange calcite, but calcite is softer and reacts with dilute acid.