Carnelian

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Orangey-red to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.58-2.64

Formation & Geological History

Formed in volcanic environments as a precipitate from silica-rich fluids in cavities and veins of igneous rocks. Its red color comes from iron oxide (hematite) impurities. It can be found in sedimentary deposits after erosion of source rocks.

Uses & Applications

Primarily used in jewelry (beads, cabochons, carvings) and lapidary art. Historically used for signet rings and seals because hot wax does not stick to it.

Geological Facts

Ancient Egyptians called Carnelian the 'setting sun' and believed it had protective properties. It is one of the most historically significant gemstones, dating back to the Neolithic period.

Field Identification & Locations

Identified by its distinctive semi-translucent reddish-orange color and lack of banding (unlike banded agate). Commonly found in Brazil, India, Uruguay, and Madagascar. Look for waxy luster on weathered surfaces.

Identified on: 5/3/2026

Mode: Standard