Pearls come from certain mollusks, primarily marine oysters and freshwater mussels, which are types of bivalve mollusks including oysters, mussels, clams, and scallops

How pearls form:

• When an irritant such as a parasite or a foreign particle enters the mollusk's shell and cannot be expelled, the mollusk secretes layers of nacre (made of aragonite and conchiolin, the same materials as its shell) around the irritant as a defense mechanism

• This nacre coating builds up over time, forming a pearl with a characteristic lustrous surface known as mother-of-pearl

• The process can take from several months up to several years depending on the mollusk and nacre production rate

Where pearls are found:

• Natural pearls have historically been found in many parts of the world, especially in the Indian Ocean, Persian Gulf, Red Sea, Gulf of Mannar (Sri Lanka), South China Sea, and coastal waters near Australia

• Today, cultured pearls are farmed in regions like China (freshwater pearls), Japan, French Polynesia, and Australia (saltwater pearls)

• Natural pearl diving still occurs but is rare and pearls from wild oysters are increasingly scarce

In summary, pearls originate inside living mollusks as a natural protective response to irritants, forming unique organic gemstones found in both freshwater and marine environments worldwide