mineral

Carnelian Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Hardness: 6.5-7 on the Mohs scale. Color: Brownish-red to orange. Luster: Waxy to vitreous. Crystal Structure: Trigonal (microcrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Brownish-red to orange
Luster: Waxy to vitreous

Identified March 13, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater into the cavities of igneous rocks. The reddish color is caused personally by iron oxide (hematite) impurities. It can be found in volcanic rocks ranging from prehistoric eras to more recent geological formations.

Uses & applications

Predominantly used for lapidary work, jewelry (cabochons, beads), and decorative carvings. Historically, it was used for making cylinder seals and signet rings because hot wax does not stick to it.

Geological facts

Carnelian was highly prized in Ancient Egypt, where it was believed to assist the soul on its journey into the afterlife. It is one of the oldest semi-precious stones used in human history, dating back to at least the Neolithic period.

Field identification & locations

Identify in the field by its distinctive waxy luster, translucency when held to light, and irregular conchoidal fractures. Commonly found in Brazil, India, Madagascar, and Uruguay. Collectors should look for alluvial gravels or volcanic outcrops.

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