Carnelian (Orange Chalcedony)

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Translucent orange to reddish-brown; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline/cryptocrystalline); Cleavage: None; Specific Gravity: 2.58–2.64.

Formation & Geological History

Formed through the deposition of silica from groundwater in cavities of igneous rocks (like basalt) or sedimentary environments. The orange hue comes from hematite (iron oxide) inclusions.

Uses & Applications

Extensively used as a gemstone in jewelry (cabochons), beads, and intaglios. Historically used for seal stones and amulets.

Geological Facts

In ancient times, carnelian was believed to give courage in battle and help speakers become bold. It is the most famous variety of chalcedony and has been used for jewelry for over 4,500 years, appearing in Sumerian and Egyptian burials.

Field Identification & Locations

Identify by its translucent 'glow' when held to light, waxy luster, and lack of visible crystalline structure. Commonly found in Brazil, India, Uruguay, and Madagascar.

Identified on: 4/13/2026

Mode: Standard