At the 2005 Tucson Gem shows, Emiko Pearls International Inc. (Bellevue, Washington) had some cultured pearls marketed as "Chocolate Pearls," that were processed to lighten their color. Although this attractive product has been available for 4-5 years, many in the trade are still unaware of it. The colors range from a pleasing dark brown to light yellow-brown, and have been described in the trade as "copper," "bronze," or "honey" colored; these hues are not typical of natural-color Tahitian cultured pearls. The luster of the "chocolate" cultured pearls varies from satin-like to metallic. The available sizes range from 9 to 15mm, although larger ones have been produced. Production is limited to a few hundred per month because only certain Tahitian cultured pearls can be successfully treated.
The coloration of these cultured pearls results from a proprietary two-stage process. Ron Greenidge of Emiko Pearls International kindly provided the general information from the company that performs the procedure. The first step is to remove color from the selected Tahitian cultured pearls, which would be compared to the bleaching process used on Akoya cultured pearls. In the second step, the bleached color is stabilized. The company reported that the process does not involve the use of dye or heat, and the brown color is stable under conditions associated with routine wear. Since Emiko Pearls International began selling the "chocolate" cultured pearls when they were first introduced to the market, they have not encountered any problems with color stability.
The exact nature of the process remains undisclosed, and future studies are needed to establish identification criteria. Preliminary research suggests that careful observation of the long-wave UV fluorescence will likely be helpful in identifying these cultured pearls, when compared to known natural colors as reference.