mineral

Carnelian (Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7 (Mohs scale), Color: Reddish-orange to brownish-red, Luster: Vitreous to waxy, Crystal Structure: Trigonal (microcrystalline/cryptocrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Hardness: 6

Identified June 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed in low-temperature hydrothermal environments, often found as fillings in veins or volcanic rock cavities. The red color is caused by iron oxide impurities that can be enhanced by heat treatment or sun exposure over geological eras.

Uses & applications

Commonly used in jewelry (beads, cabochons), lapidary art, and metaphysical collecting. Historically significant for making cylindrical seals and signet rings.

Geological facts

Ancient Egyptians referred to carnelian as 'the setting sun' or 'the blood of Isis.' It was one of the first stones used by humans for jewelry-making and is mentioned in various historical texts spanning thousands of years.

Field identification & locations

Identify by its translucent to semi-opaque reddish-orange hue and lack of visible crystalline structure. Commonly found in Brazil, India, Madagascar, and Uruguay. Field identification involves a hardness test (it will scratch glass) and checking for its signature waxy luster when broken.

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