mineral

Carnelian Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Hardness: 6.5-7 (Mohs); Color: translucent orange to reddish-brown; Luster: waxy to vitreous; Crystal Structure: microscopic trigonal; Cleavage: none (conchoidal fracture); Specific Gravity: 2.58–2.64

Hardness: 6
Color: translucent orange to reddish-brown
Luster: waxy to vitreous

Identified March 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities and veins of volcanic or sedimentary rocks via silica-rich water deposition. Often found in basalt vugs or as stream-rolled pebbles. Ages vary from Cenozoic to Precambrian depending on the parent formation.

Uses & applications

Primarily used for lapidary arts, jewelry (cabochons/beads), decorative carvings, and as a semi-precious collector gemstone.

Geological facts

Carnelian was used by the ancient Egyptians to make amulets and by Romans for seal rings because hot wax does not stick to it. The color is caused by iron oxide impurities.

Field identification & locations

Identify by its waxy luster, bright orange-red translucent color, and conchoidal (shell-like) fracture pattern. Commonly found in Brazil, India, Uruguay, and the US (Pacific Northwest). Collectors look for vibrant saturation and high translucency.

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