Please tell me about pearls. Where are they found?

Pear ls are a type of gem stone that are found in the shell s of m oll us ks , such as o yst ers , cl ams , and m uss els . They are formed by the de position of layers of n acre , a type of calci um carbon ate , around a foreign object , such as a piece of sand or a piece of shell . \n \n P ear ls can be found in many different parts of the world , including the Pacific and Atlantic O ce ans , the Gulf of Mexico , and the Indian Ocean . They are often harvest ed from wild o yst ers , but they can also be far med in pear l farms , where o yst ers are raised and harvest ed for their pear ls . \n \n P ear ls are highly valued for their beauty and r arity , and they are often used in jewelry and other decor ative items . They come in a wide variety of colors , shapes , and sizes , and each pear l is unique . </s>