mineral

Precious Coral (Red Coral)

Corallium rubrum (Calcium Carbonate, CaCO3)

Hardness: 3.5-4.0; Color: Pale pink to deep red; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 2.6-2.7.

Hardness: 3
Color: Pale pink to deep red
Luster: Vitreous to dull

Identified May 25, 2026More mineral →

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Physical properties

Hardness: 3.5-4.0; Color: Pale pink to deep red; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 2.6-2.7.

Formation & geological history

Organic origin: formed by the skeletal remains of marine polyps in subtropical and tropical waters, typically found in the depths of the Mediterranean Sea and around Japan and Taiwan.

Uses & applications

Primarily used in jewelry making (beads, cabochons, carvings) and as ornamental gemstone; historically used as a status symbol and for supposed medicinal properties.

Geological facts

Unlike most gemstones which are minerals of mineraloid origin, coral is an organic gemstone created by living organisms. It has been harvested for over 5,000 years, and red coral is the most sought-after variety.

Field identification & locations

Identify by looking for characteristic 'growth rings' or wood-grain patterns under magnification. Most commonly found in jewelry shops or coastal regions. Avoid fakes made of plastic or glass that lack internal structure.

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