Why are pearls different colors?

Pearls come in a variety of colors and shades, from white, cream, and pink to black with blue, green, or purple overtones, with white, cream and grey the popular. The type of oyster, the thickness and number of layers of nacre, and possibly trace elements in the oyster's aquatic environment are some of the reasons for different colors as well as the base color, overtone, and iridescence. Cultured pearls are also sometimes dyed.

The color of a pearl depends on the Oysters environment.

Most pearls are white, sometimes with a creamy or pinkish tinge, but may be tinted with yellow, green, blue, brown, or black.

The unique luster, or orient, of pearls depends upon the reflection and refraction of light from the translucent layers and is finer in proportion as the layers are thinner and more numerous. The iridescence which some pearls display is caused by the overlapping of successive layers, which breaks up light falling on the surface.

South sea pearls are the color of their host oyster's mantle - and can be white, silver, pink, gold, cream, and any combination of these basic colors, including overtones of the various colors of the rainbow displayed in the pearl nacre of the oyster body itself.

Additional Information While the environment is a factor in a pearl's color it is a limited factor. The strongest defining factor is the type of mollusk. Different pearl mollusks produce different color for different reasons. South Sea Pearls

South Sea pearls are produced by the Pinctada maxima mollusk. There are two common varieties used in perliculture. The first is the silver-lip and the second is the gold lip. These colors refer to the the color of the mantle and the mother-of-pearl (nacre) which the mantle produces. The silver-lip is responsible for producing white, silver and white with rose overtone South Sea pearls while the gold-lip produces gold, yellow and champagne pearls. Of the two varieties, deep golden South Sea pearls are the most valuable, considered the most valuable cultured pearls in the world. Tahitian Pearls of Black South Sea pearls

These are pearls produced by the Pinctada margaritifera mollusk, otherwise known as the black-lip. Similar to pearls produced by the Pinctada maxima, the color is determined by the mantle color, specifically the color of the donor mantle tissue used in the grafting operation. Freshwater Pearls

Freshwater pearls come in a variety of natural colors. The colors are due to a myriad of reasons including but not limited to; the environment, the type of mussel used (Hyriopsis cumingii, Hyriosis schlegeli or Cristaria plicata), and the location of the graft within the host mussel's mantle tissue. Aniline Organic Dyes, Cobalt-60 Irradiation and Heat

Some pearls are treated to attain their colors. Many freshwater pearls are dyed in fancy bright colors, and many freshwater and akoya pearls are dyed dark. The dyes are aniline organic. Cobalt-60 radiation is also used to alter the validity of the manganese content in freshwater pearls and akoya pearl nuclei. Manganese is only present in freshwater mussel shell. It will darken freshwater pearls and darken akoya pearl nuclei which is composed of freshwater mussel shell. This will produce a dark, gray effect.

Heat is also used, primarily in Tahitian pearls, to attain the currently popular chocolate coloration.