mineral

Carnelian Agate

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7 on Mohs scale; Color: Orange, red, brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64

Hardness: 6
Color: Orange, red, brownish-red
Luster: Vitreous to waxy

Identified May 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed primarily in volcanic environments where silica-rich fluids permeate cavities in lava; the red color comes from iron oxide (hematite) impurities. These can range from modern formations to hundreds of millions of years old.

Uses & applications

Extensively used in jewelry (cabochons, beads), decorative carvings, and historical talismans or signet rings. Also popular in metaphysical and crystal collecting communities.

Geological facts

Carnelian was used by ancient Egyptians to ward off the 'evil eye' and was often buried with the dead as an amulet for the afterlife. It was also favored by the Romans for seal rings because hot wax does not stick to it.

Field identification & locations

Identified by its distinctive semi-translucent orange-to-red banding and waxy luster. Commonly found in Brazil, India, Uruguay, Madagascar, and parts of the United States. In the field, look for nodules with a smooth, weathered exterior that reveal vibrant orange centers when broken.

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sedimentary

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Schist

Metamorphic

Epidote

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Gypsum (variety Selenite or Alabaster)

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Mineral

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Mineral/Rock