Coral is the gemstone of the week, even though it is not a mineral gemstone, but rather a macrobiotic substance formed from small plant like sea life. Most commonly found in red, pink (angel skin) and white, coral also occurs naturally in blue, orange, violet, red, gold and black. The ox-blood red coral is the color that is most valued for jewelry. Coral that comes from Italy is said to be the best quality.
The basic composition of coral is calcium carbonate with a little magnesium and a trace of iron. It is semi-translucent to opaque and is relatively soft. On the Moh scale, the hardness is 3.5 to4. Coral is actually the skeletal remains of marine polyps. The polyps are surrounded by a fleshy skin and secrete a substance that allows the coral to grow. Over the centuries, the names that different corals are given have been based a lot upon their shapes. Bamboo coral resembles bamboo shoots, brain coral, the human brain, mushroom coral, mushrooms, sponge coral, sponges and so on.
Coral is found in many parts of the world. The best quality red coral is found in the Mediterranean Sea, the the Red Sea and the sea around Japan. Pink coral, or angel skin coral, is found in limited amounts in the Mediterranean area, China, India and Japan. The pink Hawaiian coral is also quite well known. Blue coral is found in the sea around the Philippines. Black coral is found around Hawaii, Australia, the West coast of Africa and parts of the Mediterranean. There is not much demand for the blue and black kinds, so the price for those is not as high as the prices for red and pink coral.
The most common enhancement for coral is dying. This is done to either change color or to make the color more uniform. Sometimes it is bleached. Coral is often filled and coated with an epoxy substance to fill cracks and cavities.
Many species of coral are endangered, but not all of it. Some coral, like bamboo and sponge coral are farm grown specifically for the market place. They are fast growing corals that are harvested in shallow water farms which makes them a sustainable resource. Global warming, pollution and harvesting for aquariums are the major causes of coral depletion.
Another form of coral that is popular for jewelry is Fossil Coral. Since that is a whole different variety, I will use another post to talk about that.
It is believed that coral can aid in the healing of lung, stomach and heart problems and help with circulation issues. It is also said that it helps in the development of courage, initiative and vitality.
Mushroom coral and Bamboo coral