mineral

Polished carnelian agate

Microcrystalline quartz (chalcedony), SiO₂; iron-oxide coloring

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent orange, reddish-brown, and gray-brown with a polished vitreous-to-waxy luster. Trigonal quartz structure; no visible cleavage and conchoidal fracture.

Identified October 16, 2026More mineral →

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Physical properties

Mohs hardness 6.5–7; translucent orange, reddish-brown, and gray-brown with a polished vitreous-to-waxy luster. Trigonal quartz structure; no visible cleavage and conchoidal fracture.

Formation & geological history

Silica-rich fluids deposited chalcedony in rock cavities, with iron oxides producing the orange-red color; the stone was later tumbled and polished. Chalcedony forms in many geological ages, commonly in volcanic rocks and sedimentary settings.

Uses & applications

Used for beads, cabochons, ornaments, and small carvings; historically valued for seals and jewelry.

Geological facts

Carnelian is an orange-to-red variety of chalcedony, and its color may be enhanced by heating. The specimen’s rounded shape and glossy surface indicate human polishing.

Field identification & locations

Identify by its translucency, waxy luster, hardness, and lack of cleavage; common sources include India, Brazil, Uruguay, and Madagascar. Similar-looking dyed agate may show unusually uniform or sharply banded color.