gemstone

Polished carnelian (red-orange chalcedony)

Carnelian, a microcrystalline variety of quartz (SiO₂), commonly colored by iron oxides

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange-brown to red, vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. The rounded, glossy surface indicates a tumbled or polished specimen.

Identified September 1, 2026More gemstone →

Explore Polished carnelian (red-orange chalcedony) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron producing the red-orange color; deposits range from Paleozoic to younger volcanic and sedimentary settings. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.

Uses & applications

Used for cabochons, beads, carvings, seals, and ornamental objects; durable enough for jewelry and small decorative pieces. Common polished specimens typically have modest market value.

Geological facts

Carnelian is chalcedony rather than a distinct mineral species; color may be enhanced by heating. It was widely used for ancient seals and amulets, especially in Egypt, Greece, and Rome.

Field identification & locations

Identify it by its even orange-red color, translucency, waxy polish, and lack of large quartz crystals; it should scratch glass but not be scratched by a steel blade. Natural-looking specimens may show cloudy bands or iron staining.