mineral

Carnelian

Chalcedony (SiO2) with iron oxide impurities

Hardness: 6.5–7 on the Mohs scale. Color: Orange to reddish-brown (translucent). Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal) microcrystalline. Cleavage: None. Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Orange to reddish-brown (translucent)
Luster: Vitreous to waxy

Identified March 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic and sedimentary rocks as groundwater rich in silica deposits material in gas cavities or fractures. The color is derived from hematite (iron oxide) inclusions. Deposits are found worldwide in geologic ages ranging from the Cretaceous to the modern day.

Uses & applications

Predominantly used for jewelry, lapidary arts, beads, and cabochons. Historically used for signet rings and cylinder seals due to its property of not sticking to hot wax.

Geological facts

Carnelian was highly prized by the ancient Egyptians as a stone of the sunset and by the Romans for seals. It is the most common variety of chalcedony used in jewelry. Heat treatment is often applied to lighter colored agates to deepen the red-orange hue by oxidizing the iron content.

Field identification & locations

Identify in the field by its characteristic waxy luster and translucent orange-red body color. Commonly found in riverbeds or coastal areas of India, Brazil, Uruguay, and Madagascar. Collectors look for uniform color and high translucency.

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