Carnelian

Physical Properties

Hardness: 6.5-7.0 (Mohs); Color: Orange-red, brownish-red, or translucent orange; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (Trigonal), Microcrystalline; Cleavage: None; Specific Gravity: 2.58-2.64.

Formation & Geological History

Formed in low-temperature hydrothermal environments typically as fillings in cavities of volcanic rocks (basalt). The color is derived from iron oxide (hematite) impurities. It can be millions of years old, often found in ancient volcanic deposits.

Uses & Applications

Mostly used in jewelry (beads, cabochons), lapidary art, and making seals or intaglios since ancient Roman times. It is also a popular collector's mineral and a 'birthstone' alternative.

Geological Facts

Ancient Egyptians called carnelian 'the setting sun' or 'vibrant sun.' It was widely used in ancient civilizations for signet rings because hot wax does not stick to it. It is a variety of chalcedony.

Field Identification & Locations

Identify by its translucent, waxy appearance and warm reddish-orange color. Unlike jasper, it is translucent when held to light. Common locations include India, Brazil, Uruguay, Madagascar, and the USA (Oregon and Washington).

Identified on: 4/13/2026

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