mineral

Carnelian Agate

Silicon Dioxide with Hematite impurities (SiO2 + Fe2O3)

Hardness: 6.5-7 (Mohs); Color: Translucent orange to reddish-brown; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal) microcrystalline; Cleavage: None; Specific Gravity: 2.58–2.64

Hardness: 6
Color: Translucent orange to reddish-brown
Luster: Vitreous to waxy

Identified March 28, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Translucent orange to reddish-brown; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal) microcrystalline; Cleavage: None; Specific Gravity: 2.58–2.64

Formation & geological history

Formed through the deposition of silica in gas cavities (vesicles) within volcanic rocks or ancient sedimentary layers. Its red/orange color is derived from iron oxide (hematite) impurities. It can be found in formations ranging from recent to hundreds of millions of years old.

Uses & applications

Predominantly used as a gemstone in jewelry (cabochons, beads), decorative carvings, and in alternative healing practices. Historically used for making signet rings and cylinder seals as hot wax does not stick to it.

Geological facts

Carnelian was highly prized in ancient Egypt, where it was believed to give spirits wings for the journey to the afterlife. It is one of the oldest known gemstones, with archaeological evidence of its use dating back to the Neolithic period (4th-5th millennium BC).

Field identification & locations

Identify in the field by its waxy luster, conchoidal fracture, and lack of visible crystal faces. It is commonly found in riverbeds or beaches in regions of Brazil, India, Uruguay, and Madagascar. Collectors should look for even color saturation and high translucency.

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