White is the most common color in Coral, but a variety of other shades can be found, including pink, orange, red, and black. The rarest color is a deep red.  Coral is commonly enhanced to improve its color and durability. White coral is bleached. Pink coral is permeated with a colorless wax and orange coral is stabilized with a polymer. Black coral is sometimes bleached to create gold coral, although gold can be a natural color of coral as well. Occasionally, red coral is dyed to deepen or to make its color more uniform. All commonly used forms of coral enhancement are stable.
 
There is an ecological concern regarding coral and a lot of the coral reefs are dying off due to pollution, changes in water temperature and poaching.  To combat this concern all coral reefs are protected by various governments and coral sea farms have been created for Coral Reef Rehabilitation and Integrative Biological Research, especially in the South Seas and Australia. There is apparently still enough supply, either from new sources or stockpiled inventory, to meet demand, whether for precious red coral from the Mediterranean Sea, dyed Tibetan coral, or pink coral from the Pacific.  However, the coral industry is bracing for an eventual worldwide shortage. The availability of new coral is dwindling as underwater supplies are depleted. Japan has already imposed strict quotas on coral divers, while Italian divers must dive deeper and deeper to get new red coral. Hopefully the coral sea farms will be a new source of coral in the future, just as pearl farms have become.
 
Special care is required for Coral regardless of whether or not it is enhanced. A soft and porous gem, coral scratches and abrades easily and chlorine, alcohol, ammonia, nail polish remover, and other chemicals can damage it. Remove coral rings when washing and moisturizing your hands. Avoid exposing your coral to extreme temperatures.