Pearl is formed in a mollusc. When a tiny particle like sand grain intrudes into the oyster shell, it leads to irritation. To avoid this irritation, mollusc discharges fluid, nacre, to cover that grain with layers. This nacre forms any number of layers on it giving it lustre and certain shape. However, the shape may not be determined, but the lustre that is provided through nacre makes it a pearl. It takes several months or may be years for one pearl to form. Natural pearl is rarely available because out of 10,000 oysters may be one would produce a pearl. Therefore, to meet the demand of the pearl market, farmers started cultivating pearls by fertilizing oysters in their lagoons, and then nucleating them to form pearls. They enforce a grain in the shell which is taken out after some months or may be years. However, it is ensured that during this process none of the oysters are harmed in any way. Now apart from Japan and US, China is also into pearl business. Through the cultivation process millions of pearls of different colours, size and shape are available in the market. Akoya pearls are used to make white pearl set while Tahitian pearls are used to make black pearl jewelry. Different pearls have their own characteristics and importance –- Freshwater pearls are cultivated in lakes, ponds, rivers etc. They are produced in China in peach, white and pink shades. - Akoya pearls are traded from Japan that is well known for its lustre. White Akoya pearls are extremely on demand and they range from five to ten millimetre. - Hanadama pearls are also a sub category of Akoya pearls that are well known not only for their lustre, but also for their surface quality. - Tahitian pearls are obtained from French Polynesia and are popular for their dark colours like grey, blue, peacock and black. They are larger than other pearls and are obtained from special type of black lip oysters only. - Pearls obtained from Philippines, Australia and Indonesia is known as White South Sea gems. Their size can last till 18mm and are high in lustre quality. - Golden colour South Sea pearls add extra luxury to your look. They are best known for their gold overtone that is meant for special occasions. Pearls got recognition during Roman Empire, when only the ruling society had the authority to own them. Not only as an accessory, have astrologers recommended people to wear a pearl ring for stability and success.