gemstone

Tumbled orange-red quartz or carnelian

Microcrystalline quartz, SiO₂; likely carnelian (orange chalcedony), possibly iron-stained quartz

AI-generated identification · may be incorrect

Hardness about 7 Mohs; translucent orange-red to reddish-brown, vitreous to waxy luster, and no visible cleavage. The smoothly rounded, polished surface indicates a tumbled or water-worn specimen; internal crystal structure is cryptocrystalline if carnelian.

Identified September 18, 2026More gemstone →

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Physical properties

Formation & geological history

Carnelian forms when silica-rich fluids fill cavities and fractures, with iron oxides producing the red-orange color. It commonly formed in volcanic rocks during the Cenozoic and older geological periods; exact age cannot be determined visually.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry. Quartz varieties are also valued as lapidary and decorative materials.

Geological facts

Carnelian is a variety of chalcedony, colored mainly by dispersed hematite or limonite. Stronger, more uniform red-orange color and translucency generally increase desirability.

Field identification & locations

Common sources include India, Brazil, Uruguay, Madagascar, and parts of the United States. Test cautiously with a steel knife: genuine quartz should resist scratching; glass may look similar but is softer and often shows bubbles.