While shopping in the island jewelry stores you may encounter certain gemstones that have been subjected to various types of treatments. Most of these are continuations of natural processes. Others, however, will be treatments that are considered to be artificial. And while these treatments are legal if they are properly disclosed to you at the time of purchase, these same treatments are considered illegal if you are not told about them before you make your purchase. Here is an outline of the most used gemstone treatments about which you should be aware:
Heat Treating . . .
is a process in which the gemstones are placed inside a large brick kiln and subjected to heat for a period of hours or even days. This causes most gemstones to darken in color. Since this treatment is simply a continuation of the natural heat from the earth that formed and caused the color in the gemstone crystal, heat treatment is considered a continuation of a natural process and does not have to be disclosed. Gemstones in virtually every category are heat treated at some point before they are set in jewelry.
Fracture Filling . . .
is the process by which a substance of the same optical density as that of a gemstone is pressure filled into a fracture of that gemstone. The result is that the fracture virtually disappears. This treatment is considered to be an artificial treatment that requires proper disclosure at the time of sale. It should be noted that this treatment is very difficult to detect and some of these stones have been known to get mixed with non-treated stones. The result is that a jewelry store sells a fracture filled stone without being aware of its condition. If you suspect that you may have a fracture filled stone you should call the CGI office. Most often fracture filling is found in diamonds and emeralds though others may exist.
Oiling . . .
is a process in which a stone is coated with a resin-like oil that coats a stone. This process can be acceptable in the case of emeralds that are oiled with a clear resin type oil such as cedar oil. Since emeralds are porous, much like an opal, their surface needs to be sealed to prevent hand lotions, suntan lotions, etc. from forming deposits in these small surface breaking fissures. In this case the use of a clear oil to seal the stone is acceptable without disclosure since the clear oil does not significantly alter the appearance of the stone. However, if a green colored oil is used to enhance the color of the emerald, this is considered an artificial treatment that needs to be disclosed to you at the time of purchase.
Laser Drilling . . .
uses an intense laser bean to drill into the diamond to an inclusion. The laser then burns the inclusion out leaving a white, or sometimes clear, space in the stone where there was previously a dark inclusion. This method of treatment allows diamond clarity to be significantly enhanced. This process is used mainly for diamonds and does not harm the stone. Laser drilling is considered an artificial treatment and must be disclosed at the time of sale.
Irradiation . . .
is the process by which a gemstone is placed inside a nuclear reactor and has its internal crystal structure altered by the radiation. This altered crystal structure causes a change in the color of the gemstone. Some notable examples are green diamonds and blue topaz. While both of these colors in the respective gemstones occur naturally, they do not occur in commercially viable amounts. However, by taking off-colored diamonds and white topaz and treating them by irradiation it is possible to produce these and many other colors of gemstones.
Diffusion Treatment . . .
is commonly used to turn colorless sapphire into blue sapphire. The treatment is to coat a colorless sapphire with cobalt and then heat the stone to melt, or fuse, the cobalt into the surface of the stone. This imparts a beautiful blue color to the sapphire. The problem is that the process is only surface deep, and re-polishing, or even everyday wear of the sapphire, can cause the color to be polished or scratched off. This is a very difficult treatment to identify so you should be sure to shop with a CGI Certified Jeweler.
Dyeing . . .
is the treatment used to enhance the color of many gemstones. This is a process by which colored dyes are applied to the surface of gemstones which gives an enhanced color that will eventually wear off. Examples of dyed gemstones will be Lapis Lazuli, jade, onyx, opal, emerald, and cultured pearls. This treatment should be disclosed, but that rarely happens.