What produces the color of pearls?

In short, the black-lipped oyster is the variety that produces the natural black color of Tahitian pearls. The most well known Tahitian pearls are the natural black color, however, they are found in a wide range of colors which include: black, gray, blue, green and brown, and various hues. These colors are known as body color. Body colors are enhanced by at least one overtone colors. Overtone colors may include blue, gold, silver, pink and reddish purple. This is what causes the irridescant appearance of the Tahitian pearls.

The Tahitian pearls body color and overtone color are names such as:

Peacock: greenish black
Pistachio: greenish gray
Cherry: purplish black
Champagne: yellowish gray
Lavender: bluish black
Tahitian gold: golden black
Pigeon gray: purplish gray
Silver: gray
Moon gray: pale gray

It seems that the colors in most demand are peacock and Pistachio. Tahitian pearls with peacock and pistachio colors have a higher value than Tahitian pearls with other colors.