gemstone

Tumbled carnelian

Carnelian, a reddish-orange chalcedony variety of microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent to opaque orange-red with a waxy to vitreous luster and no visible cleavage. It has a cryptocrystalline quartz structure and typically shows subtle cloudy or banded internal texture; color commonly comes from iron oxides.

Identified August 30, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, later acquiring iron staining; many commercial pieces are heat-treated or dyed. Deposits occur in relatively young to ancient volcanic and sedimentary terrains.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and tumbled stones; historically used in seals and signet jewelry. Common-quality pieces have modest value, while vivid, translucent material is more desirable.

Geological facts

Carnelian is a member of the agate/chalcedony family and may grade gradually into orange jasper or agate. It is commonly confused with dyed orange chalcedony or glass.

Field identification & locations

Identify it by its orange-red color, fine-grained waxy appearance, lack of cleavage, and ability to scratch glass; bubbles or perfectly uniform color may indicate glass or treatment. Common sources include India, Brazil, Uruguay, Madagascar, and Germany.