mineral

Carnelian Agate

Chalcedony (Silicon Dioxide, SiO2) with Iron Oxide impurities

Hardness: 6.5-7 on the Mohs scale; Color: Translucent to semi-opaque orange, red, or brownish-red; Luster: Vitreous to waxy; Crystal Structure: Trigonal (cryptocrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64

Hardness: 6
Color: Translucent to semi-opaque orange, red, or brownish-red
Luster: Vitreous to waxy

Identified March 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater into the cavities (gas bubbles) of volcanic igneous rocks like basalt. Its orange-red hue is caused by iron oxide impurities. It can be found in formations ranging from the Cenozoic era to ancient Precambrian deposits.

Uses & applications

Commonly used in jewelry (beads, cabochons, rings), ornamental carvings, and historical wax seals. It is also a popular specimen for rock tumbling and crystal collecting.

Geological facts

Carnelian was highly prized in Ancient Egypt, where it was associated with the setting sun and believed to possess protective powers for the deceased. It was also used by Ancient Romans and Greeks in signet rings because hot wax does not stick to it.

Field identification & locations

Identify in the field by its waxy luster, translucency when held to light, and lack of visible crystal grains. It is commonly found in Brazil, India, Uruguay, Madagascar, and parts of the United States (such as Oregon and Washington). Collectors look for uniform color or distinct banding in agates.

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