mineral

Tumbled orange-brown chalcedony (likely carnelian)

Microcrystalline quartz, SiO₂; carnelian is iron-colored chalcedony

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent to opaque orange-brown, with a waxy to vitreous luster and no visible cleavage. The rounded, polished surface obscures natural texture, so exact identification from the photo is uncertain.

Identified October 16, 2026More mineral →

Explore Tumbled orange-brown chalcedony (likely carnelian) in the encyclopedia →

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Physical properties

Formation & geological history

Silica-rich fluids deposited microcrystalline quartz in rock cavities; iron impurities produce the warm color. Chalcedony forms in many geological settings and occurs from ancient to relatively recent deposits.

Uses & applications

Tumbled chalcedony is used for jewelry, beads, ornaments, and collecting; industrial chalcedony is also used as a silica source.

Geological facts

Carnelian is a traditional variety of chalcedony, historically used for seals and carved jewelry.

Field identification & locations

Look for translucent orange-red color, waxy luster, and hardness sufficient to resist scratching by a steel knife; common sources include India, Brazil, and Uruguay. The pictured piece may be another iron-stained chalcedony.