Pearls: Genuine or Synthetic?

Posted by on Saturday, July 5, 2014 · Leave a Comment 

I am asked about pearls frequently, and there are really two questions to consider: First, how do you distinguish a genuine pearl from an imitation pearl? And second, how do you distinguish a natural pearl from a cultured pearl? The correct answer to both questions is of course … show your pearls to a GIA graduate gemologist whose practice includes the buying, selling, and appraising of natural and cultured pearls!

In the meantime, here is some information for you:

Natural pearls grow by themselves when a grain of sand or piece of silt floating in the ocean works its way into the shell of the mollusk (also spelled mollusc). The mollusk secretes layers of nacre around the irritant, and in the process, a pearl is formed. Natural pearls are often slightly oval or barrel shaped. The only permanent way to distinguish them from cultured pearls is by X-Ray, which will easily distinguish the size and type of nucleus that started the process going. In the 21st century, natural pearl production is fairly limited to the countries of Oman and Bahrain, where such pearls have been found for 900 years.

Regarding the identification of genuine pearls (natural and cultured) and separating them from imitation pearls (usually made of glass), this can be very difficult for the novice and for many jewelers. Glass beads have a slightly rough chemical coating around the pearl, which gives the surface the same gritty feeling as that of a genuine pearl. Looking through a drill hole can sometimes reveal a uniform passage, most common in laboratory manufactured glass beads. Sometimes a necklace of glass beads will feel lighter where a necklace of the same size cultured pearls will have more mass and more weight. Finally, glass beads will often be most totally uniform in size, quality and overall appearance, making one a bit suspicious of their origin. These are not “conclusive tests” however, only indications that could go one way or the other.

Glass beads have been manufactured for centuries. Cultured pearls were invented in the 1890’s, and pearl farming was perfected by the 1930’s. So in the years between World War I and World War II, elderly jewelers who were used to selling only natural pearls in the beginning of their careers now had to switch to cultured pearls, which were available in much greater quantity, and with much more uniform round shape, uniform skin color and uniform nacre, luster and brightness. It took those jewelers years to learn, and still more years to train their customers that a cultured pearl necklace was not an imitation, but a real necklace where the process of inducing the mollusk to secrete nacre was begun in a different fashion.

Please Leave a Comment

  • Recent Tweets