Coral is a calcareous, skeleton-like deposit of the coral polyp- a tiny invertebrate that dwells in quiet waters and is found at depths ranging from 20 to 1,000 feet. The color of coral depends on the depth at which it is found - below 160 feet its color is light. The best-colored corals are found between depths of 100 and 160 feet. It is found in many shades of red and pink. The color usually ranges from white to pink to vermilion red and deep scarlet. Corals of yellow ocher, cream, chocolate and black color are also available. A good coral that is related to the planet Mars and recommended by astrologers, gem therapists and jewelers is a deep red coral, which resembles well-ripened bimb fruit or an unripe cherry.