The principle of classification of corals is based on the color differences, geography and growths accommodation. According to science, there are about 350 color shades of corals. And their coloration primarily affects the ratio of organic and inorganic substances in the formulation. Organics can be from 1% to almost 100% of the coral formation. But most organic is black coral. Highly appreciated, black coral listed in the Red Book and not produced by industrial methods. However, the most valuable are red and pink corals. In addition, highly valued are also corals white with pink and white inclusions. But most rare are blue corals. In fact, there are three clean, free of impurities coral species – red, white, and black. Besides, there are also other brightly colored corals – pink, blue, yellow, brown, purple, and even rainbow corals.