mineral

Carnelian Agate

Red Chalcedony (SiO2 with Iron Oxide impurities)

Hardness: 6.5-7 on Mohs scale. Color: Translucent reddish-orange to brownish-red. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None. Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Translucent reddish-orange to brownish-red
Luster: Vitreous to waxy

Identified May 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the deposition of silica from groundwater in the cavities of igneous rocks, particularly volcanic lavas. The red hue is caused by iron oxide (hematite) impurities acting as a coloring agent.

Uses & applications

Extensively used in jewelry (cabochons, beads), decorative carvings, heart-shaped worry stones, and historically for signet rings and cylinder seals.

Geological facts

Ancient Egyptians called carnelian 'the setting sun' and believed it had protective properties. In Roman times, it was used for signet rings because hot wax does not stick to it.

Field identification & locations

Identify by its characteristic waxy luster and translucent orange-red color. It lacks the distinct concentric banding of typical agate but often shows cloudy inclusions or uneven color distribution. Found globally including Brazil, India, and Uruguay.

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