mineral

Carnelian Agate

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Orange, reddish-brown, pale amber; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal (Cryptocrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Orange, reddish-brown, pale amber
Luster: Vitreous to waxy

Identified June 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater in the cavities of igneous rocks. The orange color comes from iron oxide (hematite) impurities. Most commercial carnelian is originally grey chalcedony that has been heat-treated.

Uses & applications

Mainly used in jewelry, lapidary arts, and as a collector's gemstone. Historically used for signet rings and amulets due to its toughness and ability to not stick to wax.

Geological facts

In ancient Egypt, carnelian was known as 'the setting sun' and was associated with the blood of Isis. It was one of the twelve stones on the breastplate of Aaron mentioned in the Bible.

Field identification & locations

Look for a translucent, waxy appearance with a warm orange hue. It is often found in riverbeds or beaches as water-worn pebbles. Commonly found in Brazil, India, Uruguay, and the United States (Oregon/Washington).