gemstone

Precious Red Coral

Corallium rubrum (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3.5-4 Mohs; Color: Varies from pale pink to deep oxblood red; Luster: Dull (natural) to Vitreous (polished); Cleavage: None; Structure: Amorphous/Organic branches

Hardness: 3
Color: Varies from pale pink to deep oxblood red
Luster: Dull (natural) to Vitreous (polished)

Identified July 5, 2026More gemstone →

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Physical properties

Hardness: 3.5-4 Mohs; Color: Varies from pale pink to deep oxblood red; Luster: Dull (natural) to Vitreous (polished); Cleavage: None; Structure: Amorphous/Organic branches

Formation & geological history

Produced by marine polyps in skeletal colonies, typically found in rocky seabeds at depths of 10 to 300 meters, notably in the Mediterranean Sea.

Uses & applications

Primary use in high-end jewelry, beads, cabochons, and decorative carvings. Highly valued as an organic gemstone.

Geological facts

Unlike reef-building corals, precious coral grows very slowly, sometimes only a few millimeters per year. In many cultures, it was historically believed to protect against evil spirits and ensure health.

Field identification & locations

Identify by looking for longitudinal striations along the branches and a lack of air bubbles. Genuine coral will effervesce when touched with an acid like vinegar. Common in the Mediterranean and near Japan.