sedimentary

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs). Color: Translucent orange to reddish-brown. Luster: Waxy to vitreous. Crystal structure: Trigonal (cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Translucent orange to reddish-brown
Luster: Waxy to vitreous

Identified July 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms as a secondary mineral in volcanic rocks and sedimentary environments when silica-rich fluids deposit in cavities. The orange color is due to iron oxide impurities (hematite). Many specimens date from the Cenozoic era.

Uses & applications

Used primarily in jewelry as cabochons or beads, ornamental carvings, seals, and as a popular collector specimen for its vibrant color.

Geological facts

Carnelian was used by ancient Egyptians as a protective amulet and by Romans to carve signet rings for wax seals because hot wax does not stick to it.

Field identification & locations

Identify by its waxy luster, translucency, and warm orange-red palette. Common in India, Brazil, Uruguay, and Madagascar. Look for it in river gravels or weathering out of igneous hosts.