Pearls were discovered naturally many years ago, but because of over harvesting, they soon became rare and hard to find.
Thus, humans discovered a way to “trick” the mussel or oyster into producing a pearl, by nucleating, or implanting a mollusk with a substance – a bead or a piece of tissue - to induce cultured pearl formation.  Once the mollusk discovers the “intruder” or the object placed inside of it, it then begins to cover it with nacre (nay-kruh).  Therefore creating a beautiful pearl!  Because pearls are made by living creatures, they are an organic gem! 

Shapes of objects vary depending on the final shape of that is desired. The depth of nacre coating depends on the type of mollusk involved, the water it lives in, and how long the intruder is left in place before harvested. As nacre thickness increases, so does the quality and durability of the cultured pearl.

Pearls are also known in many cultures for their ability to balance the body with nature, and also to help in stressful situations.       

There are many types of pearls; freshwater pearls are grown in mussels that live in fresh water:  mainly from lakes and ponds; and saltwater pearls are grown in oysters in saltwater oceans and bays. 

Freshwater Pearls

Freshwater Pearls are grown in mussels, which live in fresh water.  

They are commonly found in China, Japan, and the U.S. When the mussel is 6 months old, a Nucleator (someone who is trained to nucleate, or place a piece of mantle tissue inside of a mollusk) puts a piece of mantle tissue inside of the mollusk and then the mollusk will cover the intruder with nacre to produce a pearl! After 2-6 years, a mussel will create a beautiful pearl! 

These pearls are usually 4-11mm in size, but one can find much smaller or larger pearls. They naturally come in many colors, which include:  white, cream, yellow, orange, pink, and purple. When these pearls are treated or dyed, one can find them in any color imaginable, such as: black, brown, blue, to name a few. Because they are nucleated with mantle tissue, these pearls are mostly all nacre. They are rarely spherical and only 2% of freshwater pearls are round or near round. 

The culturing of blister pearls, which is a pearl grown around a nucleus that is glued under the mantle inside the mollusk’s shell, began in China by the 13th Century.  Yu Shun Yang began the culture blister pearl industry from Lake Tai, near Shanghai. 

These 13th Century nucleators used bamboo sticks to open the mussel’s shell to insert the tissue to be covered by the mussel. The farmer would then keep the mussels in a canal, stream, or pond for six months until harvesting the mussel, or taking out the pearl.   Today most Chinese Freshwater Pearl farming takes place within about 300 miles of Shanghai. 

Saltwater Pearls

Saltwater Pearls are grown in oysters, and are:  Akoya, Tahitian, and South Sea. 

These oysters are nucleated by placing a bead (made from a mussel’s shell) into their shells and are covered with nacre. Therefore, about 80% of saltwater pearls are round.

Akoya Pearls are grown in a small oyster. Akoya oysters can be found off the coast of Japan and China. Because of Akoya pearls are typically round, and well matched, they created the phrase “strand of pearls”. They are the smallest of other oysters, and can be 2-9mm in size. They are 24-36 months at first nucleation, and take 8-24 months to grow a pearl. 

Tahitian Pearls are grown in the large Black Lipped Oyster.  Because the inside edges of this oyster are black, the Tahitian pearl has a darker, blackish coloring. These pearls can come in many shapes, and are usually 9-13mm in size, and about 40% of these pearls are round or near round. They are first nucleated at the age of 30-36 months, and take 22-26 months to create a pearl.

South Sea Pearls are grown in the Large Gold and Silver Lipped Oyster, which is one of the largest pearl producing mollusks. South Sea pearls are the largest cultured pearls on the market, and these oysters can be found in Australia, Philippines, and Indonesia.  These pearls can also come in many shapes, but tend to be very lustrous and round. They usually are 9-20mm in size. The oyster is 24 months when it is first nucleated with a bead.

NOTE:  All the information provided is from the Gemological Institute of America: www.gia.edu