Michon Jewelry Blog

It used to be that pearls were (usually) white or off-white, but today, pearls come in just about any color you can think of. However, most of the colors - even some whites and off-whites - are not natural. Many of the new pearl colors are obtained by dying pearls after they are harvested. Freshwater pearls in particular are often dyed. Many of the dyes being used are very stable - they won’t wash off or fade - so in general, it is perfectly safe to purchase pearls and/or pearl jewelry in dyed colors. I’ve heard of people’s pearls fading with exposure to sunlight, or from being rinsed in water, but so far this has never happened to me personally.

Besides dying pearls, there are a few other methods used to color pearls. Heating them can produce desirable colors, as can irradiation. I don’t know very much about these processes, but I do know that these processes are used to turn freshwater pearls into darker, tahitian-like hues. I’ve never had problems with heated or irradiated pearls losing their color.

Another common process for changing the color of a pearl is bleaching. A lot of people believe that most pearls are white when they come out of the oyster, but this is not really true. It is more common for pearls to have a peachy or beigy color naturally, and they are then bleached if a bright white color is desired. I should point out here, though, that naturally white pearls do exist - they just aren’t as common as many people believe, based on the large quantities of white pearls on the market.

So, which colors are natural, and how can you tell if your pearls are natural in color? Often, you won’t be able to tell, but a few things to consider:

• Natural colors include white, pale pink, pale peach, off-white, beige, gold, grey, and black. Any color that is a ‘classic’ pearl color is probably a color that does occur in nature - but these colors are also produced using dyes, bleach, heat, and irradiation treatments (and probably other treatments that I’m not aware of yet).
• Colors that are likely dyed include very bright colors and very unnatural looking colors, and any pearls where you can see spots where the dye pooled a little and left spots on the pearl that are darker than the rest of the pearl. Sometimes you can see the dye near the holes of drilled pearls. However, it is not always possible to tell so easily whether a pearl has been dyed. Very expensive pearl jewelry should probably be checked by a gemologist for possible treatments, since they are not always visible to the naked eye.
• Colors that are likely to be either heated or irradiated include golds, blacks, purplish blacks, and greenish blacks. As I said before, I don’t know a lot about these treatments other than the fact that they are used to color pearls. Because black pearls and gold toned pearls are very popular today, freshwater pearls are often treated to obtain these desirable colors. It would be very hard to tell just by looking at a strand of pearls if they had been treated with heat or irradiation, so if it is important to know, I recommend getting advice from a certified gemologist. There is specialized equipment to detect these kinds of treatments.
• White pearls are often bleached. Not all white pearls have been bleached, so again, if you aren’t sure and you want to be sure, get them analyzed by a professional.

Those are the common treatments I know of to change the color of a pearl. I personally don’t have a problem with color treatments for pearls. The resulting colors are often very beautiful, and the colors seem to be very stable, in general. What I do have a problem with is misrepresentation - a dealer (or jeweler) should not claim that their pearls are natural colors unless they are absolutely sure that the pearls have not been treated. So many pearls these days are treated in some way to improve their appearance, and color treatments are very common. I never assume that pearls are natural colors, even if the color is one that could be natural, because you really never know unless you can afford to have them tested. My advice to people considering purchasing very expensive pearl jewelry is to have it tested, or buy it from a trustworthy and knowledgable source. My advice to people buying less expensive pearl jewelry is to simply understand that the pearls may have been treated in some way to improve their appearance. Sometimes the cost of having pearls tested is more than the cost of the pearls themselves, so it is not always practical.