gemstone

Tumbled orange chalcedony (likely carnelian)

Carnelian, a cryptocrystalline variety of quartz (SiO₂)

AI-generated identification · may be incorrect

Typically translucent orange to reddish-orange with a waxy or glassy luster; Mohs hardness 6.5–7, no visible crystals, and conchoidal fracture. The smooth oval shape indicates mechanical tumbling and polishing.

Identified August 11, 2026More gemstone →

Explore Tumbled orange chalcedony (likely carnelian) in the encyclopedia →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, often with iron-oxide coloring; deposits commonly range from Paleozoic to Cenozoic age. Exact identification cannot be certain from a photograph alone.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry; polished pieces are popular as pocket stones and lapidary material.

Geological facts

Carnelian’s orange-red color is caused mainly by dispersed hematite or limonite. Heat treatment can intensify its red-orange color, and much commercial material comes from India, Brazil, Uruguay, and Madagascar.

Field identification & locations

In the field, look for uniform orange coloration, translucency at thin edges, a waxy surface, and hardness sufficient to scratch ordinary glass; test unobtrusively because polished surfaces can be damaged. The gray disk appears to be a separate stone, possibly slate or another fine-grained rock.