Carnelian (Banded Agate)

Physical Properties

Hardness: 6.5-7 on Mohs scale; Color: Orange, red-brown, translucent; Luster: Waxy to vitreous; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.64

Formation & Geological History

Formed through the deposition of silica in gas cavities (vesicles) of volcanic rocks or within sedimentary veins. Its reddish hue comes from iron oxide impurities (hematite) during formation.

Uses & Applications

Used primarily in lapidary work for jewelry (cabochons, beads), decorative carvings, and as a collector's specimen. Historically used for signet rings and amulets.

Geological Facts

Ancient Egyptians called carnelian 'the setting sun' or 'the sunset stone' and believed it could protect the soul in the afterlife. It was also used by Romans to create seal rings because hot wax does not stick to it.

Field Identification & Locations

Identify by its waxy luster, orange-to-red translucency, and lack of visible crystals. Often found in riverbeds or gravel deposits where volcanic activity once occurred.

Identified on: 4/18/2026

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