Precious coral of Mediterranean Sea
Precious coral, (Corallium rubrum), or Red coral, is the common name given to a genus of marine corals, Corallium. The distinguishing characteristic of precious corals is their durable and intensely colored red or pink-orange skeleton, which is used for making jewelry. Red corals grow on rocky seabottom with low sedimentation, typically in dark environments-either in the depths or in dark caverns or crevices. The original species, Corallium rubrum (formerly Gorgonia nobilis), is found mainly in the Mediterranean Sea. corallo rosso del mediterraneo
It grows at depths from 20 to 200 meters below sea level, although the shallower of these habitats have been largely depleted by harvesting. The same species is also found at Atlantic sites near the Strait of Gibraltar, at the Capo Verde Islands and off the coast of southern Portugal. Other Corallium species are native to the western Pacific, notably around Japan and Taiwan; these occur at depths of 350 to 1500 meters below sea level in areas with strong currents. In common with other Alcyonacea, red corals have the shape of small leafless bushes and grow up to a meter in height.
Their valuable skeleton is composed of intermeshed spicules of hard calcium carbonate, colored in shades of red by carotenoid pigments. In living specimens, the skeletal branches are overlaid with soft bright red integument, from which numerous retractable white polyps protrude. The polyps exhibit octameric radial symmetry. The hard skeleton of red coral branches is naturally matte, but can be polished to a glassy shine. It exhibits a range of warm reddish pink colors from pale pink to deep red; the word coral is also used to name such colors.
Owing to its intense and permanent coloration and glossiness, precious coral skeletons have been harvested since antiquity for decorative use. Coral jewellery has been found in ancient Egyptian and prehistoric European burials, and continues to be made to the present day. It was especially popular during the Victorian age.
(extract from Wikipedia)
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