I have a strand of black color pearl necklace . I would like to know if they were natural colored or dyed. Is
there any way that I can tell if their color are dyed or natural?
I guess, most likely, your black color pearls are artificial-colored , not natural black color. Only genuine Tahitian pearls have natural black color.
It's very very common that pearl farmer always process their pearls after harvest in one way or another. Dyeing color is not very commonly used nowadays as before, because of the emergence of new pearl treatment techniques , like Irradiation.
Irradiation pearl treatment is to use of gamma rays to darken the nucleus of the pearl in akoya pearls and the nacre layers in freshwater.
Irradiation has differing effects from freshwater to saltwater cultured pearls. The gamma rays do not affect the nacre layers of a saltwater cultured pearl, but in fact darken the nucleus of the pearl. An irradiated saltwater pearl appears to be gray or blue. The nacre of freshwater irradiated pearls, on the other hand, if affected by the gamma rays and can become very dark. Some of these freshwater treated pearls will also have an intense metallic sheen and iridescent orient over their surface.
If you would like see the natural colored pearls, please check this item of mine, 120042213617. Although its color is not very impressive comparing to those artificial-colored pearls, but the color is natural color. As you can see from the photo, the color on each pearl has some very slight discrepancies, this is the characteristic of natural color pearls .
Although nearly all pearls on the market today have been treated in some way, it can be difficult to detect pearls treated to change color. One method of detecting dyed or irradiated pearls is to check the matching of the strand. A strand of natural color pearls will typically vary slightly from pearl to pearl. A perfectly consistent strand may be evidence of treatment.
Some of the sellers are reluctant to disclose the fact that the color of their pearls are artificially colored, but the real pearl collectors should always know that pearl treatments are very commonly used as the major pearl processing methods.
Please keep this in mind, if you are purchasing black color cultured freshwater or Akoya saltwater pearls, the black color are most likely NOT natural black color.