Precious Coral, (Corallium rubrum), also known as red coral, is a species of marine coral found mainly in the Mediterranean Sea, where it grows at depths from 30 to 1000 feet below sea level. Its habitat is typically rocky sea bottom with low sedimentation, and usually in dark environments, such as caverns and crevices. Most of its shallow range has been depleted by harvesting.
While mainly a Mediterranean species, it can also be found in some Atlantic sites near the Straits of Gibraltar and the Cape Verde Islands. Other species of Corallium are native to the Pacific, notably around Japan and Taiwan, where they occur at depths upwards of 5000 feet below sea level.
The distinguishing characteristic of Precious Coral is the durable and intensely colored red or pink skeleton, which is popularly used in the jewelry making trade. This coral has the shape of a small leafless bush that grows up to 3.3 feet high. The skeleton is composed of intermeshed spicules (spike-like structures) of hard calcium carbonate. The skeletal branches contain numerous protruding white polyps that can retract as necessary.
Precious coral is one of 25 known species in the Corallium genus.