gemstone

Tumbled orange chalcedony (probable carnelian)

Cryptocrystalline quartz, SiO₂; reddish-orange variety commonly called carnelian

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange-brown color, waxy to vitreous luster, no visible crystals, and conchoidal fracture. Specific gravity is approximately 2.60–2.65.

Identified August 28, 2026More gemstone →

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Physical properties

Mohs hardness 6.5–7; translucent orange-brown color, waxy to vitreous luster, no visible crystals, and conchoidal fracture. Specific gravity is approximately 2.60–2.65.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures, later hardening as microcrystalline quartz; coloration usually comes from iron oxides. Commonly Cenozoic to older volcanic or sedimentary host material.

Uses & applications

Used for beads, cabochons, carvings, and ornamental objects; historically used for seals and signet rings. Common tumbled pieces have modest collector value.

Geological facts

Carnelian is a color variety of chalcedony rather than a separate mineral species; heating can intensify its orange-red color.

Field identification & locations

Identify by its smooth tumbled form, translucent warm orange color, waxy luster, and hardness sufficient to scratch glass. Common sources include India, Brazil, Uruguay, Madagascar, and Indonesia.