gemstone

Tumbled carnelian (likely)

Chalcedony, microcrystalline quartz (SiO₂), colored by iron oxides

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent reddish-brown to maroon, with a waxy-to-glassy luster and no visible cleavage. The rounded, polished surface indicates mechanical tumbling; color may grade from orange-red to dark brown.

Identified August 15, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron impurities producing the red coloration; deposits range from Precambrian to younger volcanic and sedimentary settings. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.

Uses & applications

Used for beads, cabochons, carvings, and inexpensive collector stones; historically used for seals and ornamental objects. Small tumbled pieces generally have modest commercial value.

Geological facts

Carnelian is a red variety of chalcedony and is closely related to sard; the boundary between the names is based mainly on color intensity. The image could also represent red jasper or dyed chalcedony, which cannot be confirmed visually.

Field identification & locations

Look for uniform fine-grained texture, translucency at thin edges, and hardness sufficient to scratch ordinary glass; natural carnelian often shows subtle color zoning. A streak, specific-gravity, or gemological test is needed for certainty.