gemstone

Tumbled carnelian (probable)

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

AI-generated identification · may be incorrect

Translucent reddish-orange to brown, vitreous/waxy luster, no visible crystals or cleavage, conchoidal fracture; Mohs hardness 6.5–7 and specific gravity about 2.60. The smoothly rounded shape indicates tumbling or natural water wear.

Identified August 16, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron producing the red-brown coloration; deposits range from ancient volcanic environments to younger sedimentary gravels. Exact age and provenance cannot be determined from the image.

Uses & applications

Used for beads, cabochons, carvings, seals, and ornamental objects; common tumbled specimens are primarily collectibles and lapidary material.

Geological facts

Carnelian is often heat-treated or dyed to intensify color, and it grades into orange chalcedony and sard. Its color may appear darker when wet.

Field identification & locations

Identify by its reddish translucent body, lack of cleavage, glassy/waxy surface, and ability to scratch ordinary glass; test cautiously because coatings or look-alike glass can mislead. Common sources include India, Brazil, Uruguay, Madagascar, and Botswana.