gemstone

Carnelian (orange chalcedony)

Microcrystalline quartz, SiO₂; chalcedony colored mainly by iron oxides

AI-generated identification · may be incorrect

Typically translucent orange-red to brown with a waxy or vitreous luster; Mohs hardness 6.5–7, no cleavage, cryptocrystalline trigonal quartz, and specific gravity about 2.6. The rough fragment has a resinous orange appearance consistent with carnelian, though image-only identification is not definitive.

Identified August 16, 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 color; deposits range from Paleozoic to Cenozoic. It commonly occurs as nodules, vein fillings, or layers in agate.

Uses & applications

Used for cabochons, beads, carvings, seals, and ornamental objects; durable pieces are popular in affordable jewelry and mineral collections.

Geological facts

Carnelian is a reddish variety of chalcedony and has been used in seals and jewelry since antiquity, including ancient Egypt and Rome.

Field identification & locations

Identify by its orange-red translucency, waxy luster, conchoidal fracture, and lack of cleavage; common sources include India, Brazil, Uruguay, Madagascar, and the United States. A scratch test should be avoided on valuable specimens.