Coral
Is a gem material with historical punch: graves have been found that date back to 8000 BC containing amulets of red coral. Nowadays coral is being used for earring, necklaces, brooches, and spectacular table sculptures. The gem material coral is a calcium carbonate structure that comes from thousands of individual coral polyps. These polyps secrete a protective jacket of calcium carbonate for protection. As the colony grows these shells, they couple together into branches and reefs.

The most desirable for jewelry has been the dark red and oxblood coral. However, a delicate shade of pink called "angel skin” has also been found to have value amongst some connoisseurs." Unfortunately the desirable colors are becoming more and more difficult to find due to the fact that all coral supplies are suffering from pollution, oil spills, thermal stress caused by discharge from power plants, overharvesting and careless and destructive harvesting of coral.

Like with all things based on supply and demand, as supplies of fine red coral go down, prices have begun to go up and imitations and tarnishing increases. Some dealers have even started dyeing colorless coral to a reddish shade that experts easily recognize as fake but might fool the inexperienced appraiser or buyer, and most certainly the insurer. According to some experts, of the new coral entering the market about 90-95% of it is color-enhanced.

Another common scam is to combine shavings of coral branches with a chemical binding agent, then sell the product as genuine coral. Imitations such as shell and plastic have also been passed as coral.

True coral is sensitive to detergents, perfumes, chemicals and even body acids. Gemologists and dealers recommend that coral be cleaned periodically in a mild soapy solution to rid it of these abrasives.