Corals live at depths of between three and 300 meters in the waters around Japan, Taiwan, and in the Malaysian Archipelago, in the Red Sea, in the Bay of Biscay and around the Canary Islands, as well as in northeast Australia and the Midway Islands. In the Mediterranean, there are coral banks in the Tyrrhenian Sea, off the coast of Sardinia, off Tunisia and Algeria, former Yugoslavia and Turkey.
When we hear the word coral we first think of the coral reefs in the Southern Ocean or off Australia, of the reefs, banks and atolls which are among the most beautiful miracles of nature. However, it is not these protected coral species of which we are talking here. In jewellery, it is corals such as corallium rubrum and corallium japonicum that are used.
Corals are the product of tiny living beings which settled in enormous colonies in the depths of warm seas long before our time. The polyps, surrounded by a fleshy skin, excrete a carbonic substance from which the corals grow like trees and branches. These can attain a height of 40 cm (16"), though the actual branches seldom exceed 4 cm (1.5") . At the forks, they are somewhat thicker. It is from these parts that the precious raw material for jewellery items, large coral beads or carvings is obtained.
Corals do not necessarily have to be red, even if red is thought of as their typical color. Corals grow in nature in a wide range of colors from red to white and from blue and brown to black. The well known colors are the "blood red" Japanese Kochi coral, the pale pink "Boke," and the red "Sardegna."