What Causes Pearls to be Different Colors?

Niki Foster
Niki Foster

Pearls come in a variety of colors and shades, from white, cream, and pink to black with blue, green, or purple overtones. Many factors are responsible for the color of a pearl, but it is for the most part up to chance. A black-lipped oyster does not usually create a white pearl, and it is very rare for other oysters to produce a black pearl. Other than that, however, there is little certainty about what color pearls you can expect to harvest from certain oysters or certain areas.

Pearls come in various colors including cream, pink, and black.
Pearls come in various colors including cream, pink, and black.

The material that makes up a pearl, known as nacre, is secreted by the oyster as a response to an irritant inside the shell. Natural pearls are extremely rare and expensive and consist of concentric layers of nacre around a possibly microscopic original irritant, such as a piece of sand. Cultured pearls are made by introducing a shell nucleus, typically perfectly round, and allowing a few layers of nacre to form around it.

The factors that contribute to the color of a pearl include the type of oyster, the thickness and number of layers of nacre, and possibly trace elements in the oyster's aquatic environment. A pearl manufacturer may also influence the color of the pearl to some degree by introducing tissue from another oyster into the host oyster along with the shell nucleus. The color of a pearl is determined by a combination of factors: the base color, overtone, and iridescence. Cultured pearls are also sometimes dyed.

The thicker the nacre, the richer the color of the pearl will be, and the more iridescence it will show. Thin nacre tends to make for a milky-looking pearl with few overtones. The iridescence of a pearl is due to the overlapping layers of translucent nacre.

The color of a pearl may or may not affect its cost, though uniformity of color makes pearls more valuable. Black pearls used to be quite rare and very valuable, but they are now cultured and consequently much more widely available. Natural white pearls are rarer and more valuable than cultured black pearls. The best color is largely a matter of personal choice, or whatever most flatters one's skin tone, though regional preferences exist and may affect price.

Niki Foster
Niki Foster

In addition to her role as a wiseGEEK editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

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Discussion Comments


I found a black pearl from the flesh of a black lipped oyster of the QLD coast of Australia it is 9 to 10 mm long by 6 t0 7 mm wide it has a black and goldish line on it. It's white, but when in direct sun light it is silvery or a dark grey color. Could any one give me some knowledge on this please?


i think that if they are farmed that they inject dye into the clam. How they do this i don't know. But if it is natural the colors wouldn't be pink or bright green -- they would be brown or gray and the less common black. in the wild this happening is extremely rare.


I noticed that my pearls changes their color from pale purple then after quite some time of not being used the other half turns white? is there anything I can do to either turn it to all white?


How can I know if my fresh water cultured pearls are dyed or natural?

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