gemstone

Tumbled carnelian

Microcrystalline quartz (chalcedony), SiO₂, colored mainly by iron oxides

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange to reddish-brown, with a waxy to vitreous luster and no visible cleavage. It has a cryptocrystalline quartz structure and typically moderate specific gravity (~2.6).

Identified September 15, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when iron-bearing silica-rich fluids fill cavities and fractures, later oxidizing to produce orange-red color; commonly associated with volcanic rocks and ancient silica deposits. Its exact geological age cannot be determined from the image.

Uses & applications

Used for beads, cabochons, carvings, worry stones, and ornamental objects; attractive polished pieces have modest jewelry value.

Geological facts

Carnelian is a red-orange variety of chalcedony; paler orange material may be called sard or orange agate. Color can be enhanced by heat treatment or dyeing.

Field identification & locations

Identify by its translucent orange body, uniform waxy appearance, lack of cleavage, and ability to scratch glass; a steel knife should not scratch it easily. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.