gemstone

Tumbled banded carnelian (orange agate)

Microcrystalline quartz, SiO₂, chiefly chalcedony colored by iron oxides

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent orange to red with cream bands, waxy-to-glassy luster, cryptocrystalline structure, and no visible cleavage. The rounded surface indicates mechanical tumbling and polishing.

Identified August 31, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities in volcanic rocks, depositing chalcedony in successive layers; iron oxidation produces the orange-red color. Most specimens are Cenozoic to older, depending on the host volcanic deposit.

Uses & applications

Used for cabochons, beads, carvings, worry stones, and ornamental objects; durable and inexpensive for jewelry.

Geological facts

Carnelian is the orange-red variety of chalcedony, while banding may justify the trade name “banded carnelian” or “orange agate.” Heat treatment can intensify its color.

Field identification & locations

Identify by its translucent orange body, waxy luster, quartz-level hardness, and curved bands; it should resist scratching by a steel blade but scratch glass. Common sources include Brazil, Uruguay, India, Madagascar, and Botswana.