mineral

Tumbled carnelian (likely)

Chalcedony, microcrystalline quartz (SiO₂), iron-oxide colored variety

AI-generated identification · may be incorrect

Smooth, polished reddish-brown to orange pebble with translucent edges and glassy/waxy luster; hardness about 6.5–7 Mohs, no visible cleavage, trigonal quartz structure, specific gravity about 2.6.

Identified August 16, 2026More mineral →

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Physical properties

Smooth, polished reddish-brown to orange pebble with translucent edges and glassy/waxy luster; hardness about 6.5–7 Mohs, no visible cleavage, trigonal quartz structure, specific gravity about 2.6.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, with iron impurities producing the red-brown color; commonly Cenozoic to older volcanic or sedimentary settings. Tumbled shape is human-processed.

Uses & applications

Used for beads, cabochons, carvings, ornamental objects, and inexpensive jewelry; historically valued as a seal stone.

Geological facts

Carnelian grades from orange-red to deep brown, and heating can intensify or alter its color. Similar material may be called sard when darker brown.

Field identification & locations

Identify by its waxy luster, hardness, lack of cleavage, translucency, and resistance to scratching by steel; common sources include India, Brazil, Uruguay, Madagascar, and the United States.