Precious coral

>Habitat
Red corals grow on rocky seabottom with low sedimentation, normally in dark environments--either in the depths or in dark caverns or crevices. The original species, C. rubrum, is found mainly in the Mediterranean Sea. It grows at depths from 10 to 300 m, even though the shallower of these habitats have been largely depleted by harvesting. In the underwater caves of Alghero, Sardinia (the \"Coral Riviera\") it grows at the depth of 4 m. The identical species is also found at Atlantic websites near the Strait of Gibraltar and at the Cape Verde Islands. Other Corallium species are native to the western Pacific, notably around Japan (Corallium japonicum) and Taiwan these happen at depths of 350 to 1500 m in areas with powerful currents.
Anatomy
In frequent with other Gorgonacea, red corals have the shape of modest leafless bushes and grow up to a meter in height. Their useful 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 various retractable white polyps protrude. The polyps exhibit octameric radial symmetry.
Coral as a gemstone
Polished fragments of fake dyed red bamboo coral
Chinese coral sculpture
Non precious red dyed sponge coral earrings
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 employed to name such colors. Owing to its intense and permanent coloration and glossiness, precious coral skeletons have been harvested considering that antiquity for decorative use. Coral jewelry has been discovered in ancient Egyptian and prehistoric European burials, and continues to be made to the present day.
Precious coral has relative density of 3.86 and hardness 3.five on the Mohs scale. Due to its softness and opacity, coral is generally cut en cabochon, or utilised to make beads.
History of trade in coral
At the beginning of the Christian era, there was a outstanding trade carried on in coral between the Mediterranean and India, where it was extremely esteemed as a substance endowed with mysterious sacred properties. It is remarked by Pliny that, previous to the existence of the Indian demand, the Gauls had been in the habit of using it for the ornamentation of their weapons of war and helmets but in his day, so good was the Eastern demand, that it was pretty rarely seen even in the regions which produced it. Amongst the Romans branches of coral were hung around children\'s necks to preserve them from danger, and the substance had a number of medicinal virtues attributed to it. A belief in its potency as a charm continued to be entertained throughout medieval times and even early in the 20th century in Italy was worn as a preservative from the evil eye, and by females as a cure for sterility.
From the middle ages upwards the securing of the appropriate to the coral fisheries on the African coasts was an object of considerable rivalry among the Mediterranean communities of Europe. Prior to the 16th century they had been controlled by the Italian republics. For a short period the Tunisian fisheries were secured by Charles V to Spain but the monopoly soon fell into the hands of the French, who held the right till the Revolutionary government in 1793 threw the trade open. For a short period (about 1806) the British government controlled the fisheries, but later returned to the hands of the French authorities. Previous to the French Revolution a lot of the coral trade centred in Marseilles but since that period, both the procuring of the raw material and the working of it up into the a variety of forms in which it is used became peculiarly Italian industries, centering largely in Naples, Rome and Genoa.
Coral in mythology
The origin of coral is explained in Greek mythology by the story of Perseus. Having petrified Cetus, the sea monster threatening Andromeda, Perseus placed Medusa\'s head on the riverbank though he washed his hands. When he recovered her head, he saw that her blood had turned the seaweed (in some variants the reeds) into red coral. Thus, the Greek word for coral is \'Gorgeia\', as Medusa was 1 of the 3 Gorgons.
Poseidon resided in a palace produced of coral and gems, and Hephaestus very first crafted his work from coral.
The Romans believed coral could protect young children from harm, as nicely as cure wounds created by snakes and scorpions and diagnose diseases by changing colour.
Trivia
The two biogenic precious gemstones, coral and pearl, although drastically diverse in appearance, are chemically quite similar. Both are mostly calcium carbonate deposited by marine invertebrates.
A different unrelated species, the Hawaiian black coral is from time to time employed as an ornamental material. Its skeleton is not mineralized, consisting mostly of conchiolin.
In Vedic astrology red coral is associated with the planet Mars.
A branch of red coral figures prominently in the civic coat of arms of the town of Alghero, Italy.
References
^ a b c d \"Corallium species\". ARKive. http://www.arkive.org/coral/Coral/corallium_far more.html. Retrieved 2007-02-15. 
^ a b c \"Gemstones: Coral\". http://www.gemstone.org/gem-by-gem/english/coral.html. Retrieved 2007-02-15. 
^ a b \"Red Coral\". Marenostrum. http://marenostrum.org/vidamarina/animalia/invertebrados/cnidarios/corales/rojoi.htm. Retrieved 2007-02-15. 
^ \"Jewelry Central\". http://www.jewelrycentral.com/Target_Coral.asp. Retrieved 2007-02-15. 
^  \"Coral\". Encyclopdia Britannica (11th ed.). 1911. 
^ \"Passage from Ovid\'s Metamorphoses about the origin of coral\". http://findarticles.com/p/articles/mi_m0422/is_two_81/ai_55174794/pg_34. Retrieved 2007-03-18. 
External links
www.arkive.org Photos of living red corals and skeletons (Accessed 02 February 2007)
International Colored Gemstone Association Extensive information on gemstone coral and jewelry photos (Accessed 02 February 2007)
American Gem Trade Association Information and facts on coral as a gemstone (Accessed 02 February 2007)
Organic Gems: Red Coral Jewelry Photos of raw coral material and coral jewelry (Accessed 02 February 2007)
Mediterranean red coral: investigation team International Research Team on Mediterranean red coral (Accessed 15 March 2007)
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Categories: Anthozoa