gemstone

Polished carnelian (red-orange chalcedony)

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

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent red, orange, or brown with a waxy to vitreous luster and no visible cleavage. It is cryptocrystalline and commonly shows cloudy color zoning or internal inclusions.

Identified September 8, 2026More gemstone →

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Physical properties

Mohs hardness 6.5–7; translucent red, orange, or brown with a waxy to vitreous luster and no visible cleavage. It is cryptocrystalline and commonly shows cloudy color zoning or internal inclusions.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, later acquiring iron coloration; deposits range from Paleozoic to Cenozoic age. This specimen appears tumbled or polished.

Uses & applications

Used for beads, cabochons, seals, carvings, and ornamental objects; durable enough for jewelry but less valuable than fine transparent gemstones.

Geological facts

Carnelian is a variety of chalcedony, closely related to sard; heating can intensify its red-orange color. Ancient Egyptians and Romans used it extensively for seals and amulets.

Field identification & locations

Identify it by its orange-red translucent body, waxy polish, hardness, and lack of cleavage; common sources include India, Brazil, Uruguay, Madagascar, and Germany. The pictured specimen may also be red jasper or dyed agate, which require testing or magnification to distinguish.