gemstone

Polished carnelian (likely)

Cryptocrystalline quartz, SiO₂; orange chalcedony, commonly called carnelian

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; orange-red, waxy to vitreous luster, fine microcrystalline quartz with no visible cleavage. The pale polygonal network may be natural brecciation or surface patterning, though dyeing or coating cannot be excluded from the image.

Identified September 6, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, later becoming chalcedony; iron impurities create the orange-red color. It is commonly Cenozoic to older, depending on host volcanic or sedimentary rocks.

Uses & applications

Used for cabochons, beads, carvings, seals, and ornamental pieces; polished specimens are inexpensive but attractive collectibles.

Geological facts

Carnelian is a variety of chalcedony, closely related to agate. Heating can intensify its red-orange color by oxidizing iron.

Field identification & locations

Look for translucent orange-red color, waxy luster, lack of cleavage, and resistance to scratching by steel; glassy uniformity or color concentrated in cracks may indicate treatment. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.