Pinctada maxima, also known as Pinctada maxima, is a precious pearl shellfish unique to the South China Sea. It is shaped like a plate, and it is very big. It is generally 24 cm long and weighs 6-7 kg. The largest is more than 32 cm long and weighs 10 kg. It is the largest variety of pearl oyster. There are Pinctada martensii, Pinctada penguin, Pinctada maxima and Pinctada maxima in Hainan, and the reserves of Pinctada maxima account for about 90% of the total reserves of all kinds of Pinctada maxima in Hainan. Pinctada maxima has high economic value. Its shell is made of drugs and process raw materials, and it is widely sold in the international market at a price of 8-9 yuan RMB per catty. Its meat quality is delicious and its nutritional value is high. What's more valuable is that the pearls cultivated by Pinctada maxima have large particles, good color and high price. Pearl has always been a valuable ornament and a valuable medicinal material. It has been listed as an important medicinal material in the medical book Bielu of famous doctors in the Three Kingdoms period. At that time, there were pearls in the prestigious "Zhuge Xing Junsan". According to Li Shizhen's Compendium of Materia Medica, pearl can "cure the cloud of eyes and skin" and pearl powder "makes people moist and look good". In medicine, it has the effects of calming nerves, clearing away heat and toxic materials, diminishing inflammation and relieving pain, moistening skin, closing mouth and promoting granulation. There are more than 20 kinds of prescriptions in China, and pearls are the main drugs. Dozens of Chinese medicines, such as Liushen Pill, Anguan Niuhuang Pill, Xingjun Powder and Babao Eye Drops, all contain pearl powder. Nowadays, people also use pearl powder and skin care materials to make high-grade cosmetics such as pearl cream, pearl dew and pearl cream, which are deeply loved by people. After liberation, the pearl breeding industry in Hainan Province has developed greatly, and pearl farms have been established to cultivate pearls artificially. Artificial pearl breeding is to put the pregnant mother Pinctada after operation into a special delivery room made of nylon net. A mother pearl lives in the delivery room and is put back into the sea area with gentle water flow and rich bait to "give birth" to their "jiaozi". This process is called pearl cultivation period and needs careful management for one or even two years. Pinctada is a small creature with almost no self-defense ability. The fierce octopus and crab in the sea are the enemies of Pinctada. They will wait for an opportunity to break into the "delivery room", bite off the shell and eat their meat. Small shellfish such as oysters and barnacles in the sea also love to nest on mother-of-pearl, which seriously affects the normal growth of mother-of-pearl. In this way, pearl farming should not only guard against enemy invasion every morning and evening, but also regularly remove "hidden dangers" on pearl shells. In case of typhoon and rainstorm, you should go out to sea immediately and move mother-of-pearl to the bay. Of course, pearls are the crystallization of mother-of-pearl's life, and the crystallization of pearl farmers' sweat and painstaking efforts.