gemstone

Carnelian (orange chalcedony)

Chalcedony, microcrystalline quartz (SiO₂), iron-oxide colored

AI-generated identification · may be incorrect

Typically orange-red to brown, translucent, with waxy to vitreous luster and no visible crystals; Mohs hardness 6.5–7, conchoidal fracture, and specific gravity about 2.60. The piece appears rough or partially polished, though lighting limits certainty.

Identified August 14, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron impurities producing the orange-red color; deposits range from Precambrian to recent. It commonly occurs as nodules, veins, and agate interiors.

Uses & applications

Used for beads, cabochons, carvings, seals, and ornamental objects; historically valued in jewelry and signet rings. Common material has modest commercial value.

Geological facts

Carnelian is a variety of chalcedony, sometimes grading into orange jasper or agate. Heat treatment can intensify pale brown chalcedony to vivid red-orange tones.

Field identification & locations

Identify by its translucent orange color, smooth waxy appearance, hardness, and lack of cleavage; quartz will scratch glass, while steel generally will not scratch it. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.