How do freshwater pearls naturally gets their color?

Let's first discuss the pearl cultivation process:

1. Pearl technician cuts a strip of the mantle tissue from he donor oyster then cuts it into small pieces.

2. Opens the recipient oyster. 

3. And they nucleate the recipient oyster with the tissue.

The pearl nucleus was made by shell, which can be round, coin, or star-shaped,

it determines the shape of the pearl but not its color. The key to determining the pearl's color is the mantle tissue. The mantle tissue is a small fragment of the mantle taken from the donor mussel. The mantle is a thin membrane inside the oyster's shell that secretes nacre. 

After a small piece is inserted into the recipient oyster, a pearl sac forms on the surface of the pearl nucleus, continuously secreting nacre to form a pearl layer by layer. Interestingly, these nacre-secreting cells retain the original genetic characteristics of the donor mussel. Simply, the color of the pearl sac is the same as the color of the donor mussel. Therefore, the final color of the pearl is mainly determined by the mantle cells of the donor mussel rather than being determined by the recipient oyster.

For example, if a purple, white, or golden oyster is selected as the donor, then the pearl that eventually grows will often be the corresponding purple, white, or golden color, even if the recipient oyster itself is white. Therefore, you will see pearls of various colors growing from the same oyster.

Chinese pearl farmers use this principle to improve the color and quality of freshwater pearls, obtaining pearls with more beautiful colors, overtones, and luster through generations of selection and breeding of mother-of-pearl.

Of course, the color of a pearl is also related to the farming environment and water quality, but the captivating color of each pearl mainly depends on the gene expression of the mantle tissue.

The vibrant colors of freshwater pearls hold endless possibilities for the future.