Keith's Korner

Friendly suggestions and advice on caring for your precious jewelry.

September 15, 2010

Stone Enhancements and Treatments

One piece of information that is important when buying jewelry is stone enhancement or treatments. These enhancements are so prevalent that you should assume that all stones are treated in some way or another, unless you are told otherwise. We would rarely wear a gemstone just as it comes from the earth, in fact cutting or polishing a stone is a form of enhancement.

Most enhancements fall into several types, they are, temperature, radiation, chemicals, and surface treatments. Temperature is usually in the form of controlled heating to change the color or enhance the depth of color. Sapphires, Tanzanites , and Zircons, are normally treated in this fashion. Radiation is commonly used to enhance blue topaz, diamonds, tourmalines, quartz, and even pearls, among others. Chemicals are used in, bleaching, dying, diffusion, oiling, and impregnation. Almost all the cultured pearls in the white shades are bleached to make them uniform in color. Many stones like black onyx and other chalcedonys are dyed to make the color more uniform and sometimes to imitate other stones. Pearls are also often dyed to give colors unknown to nature, also opal and lapis are enhanced often in this way. Diffusion is done with heat and chemicals and usually affects only the very surface , we see this routinely on topaz and sapphire. Diffusion treatments are often not permanent and will wear off with extended use. Oiling is often done to enhance emeralds by filling the small cracks and fissures making the stone appear of a better quality. This last process has been done for a long time. Impregnation is placing a foreign substance like glass into the cracks of a stone using high temperature and pressure. This is used in clarity enhance diamonds and rubies, to mention a few.

Most enhancements are there to make your jewelry more attractive to the eye, only in very expensive stones should they be of concern. In these cases the difference between treated and untreated could be great. Ask your jeweler about the stones in each piece when you purchase it , and ask ,what if any, special treatment your stones require.

Most jewelers should be able to tell you what if any treatments were likely to have been used on any piece at the time of purchase. Above all enjoy your jewelry, and treat it with care.