Carnelian Agate

Physical Properties

Hardness: 6.5–7 on the Mohs scale; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (cryptocrystalline); Specific gravity: 2.58–2.64.

Formation & Geological History

Formed in volcanic and sedimentary environments through the deposition of silica-rich groundwater in cavities or veins. The reddish hue is caused by iron oxide impurities.

Uses & Applications

Commonly used in jewelry (beads, cabochons, signet rings), decorative carvings, lapidary art, and as a collector's specimen.

Geological Facts

Carnelian was used as far back as the Neolithic period. In Ancient Egypt, it was believed to assist the spirit in its journey to the afterlife and was frequently used in amulets and pharaonic jewelry.

Field Identification & Locations

Identify in the field by its translucent appearance and warm reddish-orange color. It is commonly found in Brazil, India, Uruguay, and Madagascar. It often occurs as nodules in riverbeds or within basalt cavities.

Identified on: 4/28/2026

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