mineral

Precious Coral

Corallium rubrum (Calcium Carbonate, CaCO3)

Hardness: 3.5-4 on Mohs scale; Color: Red, pink, orange; Luster: Vitreous to waxy; Structure: Amorphous/Microcrystalline; Cleavage: None; Specific Gravity: 2.6-2.7

Hardness: 3
Color: Red, pink, orange
Luster: Vitreous to waxy

Identified June 17, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 3.5-4 on Mohs scale; Color: Red, pink, orange; Luster: Vitreous to waxy; Structure: Amorphous/Microcrystalline; Cleavage: None; Specific Gravity: 2.6-2.7

Formation & geological history

Biogenic formation created by marine polyps in deep-sea environments, primarily in the Mediterranean Sea and near Japan/Taiwan.

Uses & applications

Primarily used in high-end jewelry as cabochons, beads, and carvings; also historically used for amulets and traditional medicine.

Geological facts

Unlike typical minerals formed in the earth, precious coral is an organic gemstone. It has been harvested for over 5,000 years and was highly prized by ancient Romans who believed it could protect children from harm.

Field identification & locations

Identify by looking for a characteristic wood-grain pattern under magnification and a reaction to weak acids (bubbles). Commonly found in the Mediterranean Sea.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral