Diamonds are sometimes altered chemically to improve their value, and while some are only temporarily changed, many are altered permanently. This is one of the questions you should be asking your gemologist or jeweler, as well as the carat size and points ( out of 200 for a one carat flawless diamond).A new method of enhancing diamonds is known as high pressure high temperature (HPHT). Some of these techniques can lighten imperfections of dark color stains in a diamond. In fact, as A is considered the most perfect diamonds, this color enhancement can tint a Q to Z diamond to near colorless D,E, or F.
The alteration process can turn a white diamond in to a greenish yellow, yellow green, and even fancy colors such as pink. This can be detected, but only in labs which have the expensive testing equipment. Something fortunate for the buyer is that this coloring process cn only be found in rare diamonds, those in the A and B categories, and only sub groups in that. At this point your jeweler or gemologist should be able to tell if your diamond is of that category. It is estimated that less than two percent of all diamonds are of the type to allow color changes.
These represent the majority of jewelry quality diamonds. Some are unusually large and clear, or clean. When a diamond has been altered is must be registered by the GIA, the Gemologists Institue of America. But the benefit in the transformation of a brown or yellow diamond into a white can be very great, and more than make up for the process. It is important that you have any laboratory results if alterations have been made to the stone. You should be aware that some diamonds had the annealing process before the GIA began to take rrecords, so some non verified diamonds are in existence.
You want to take care that your diamond was not part of this process, and diamonds between 1996 and June 2000 should be examined by a gemologist or jeweler to make certain. Fancy color diamonds such as pink or blue are more difficult for a gemologist to detect, so you need to take caution. This lack of clarity also applies to Type Ha and la/b diamonds as well as in some case others so testing may not work for these. If you have recently purchased a pink or colored diamond, you should have lab reports to certify what has been done to your diamond. This applies particularly if the report predates December 2000.
Radiation treatment is a powerful means to bleach, as it were, the brownish or yellowish color out of the diamond to create a white or clear, or clean diamond, and when this is done it invariably creates a more flawless, or brilliant stone. The radiation process can greatly enhance a less than noble diamond into a white or colored stone of much great value. You do want to be sure that the brilliant diamond has not been treated in this way, or that you get to see the certification papers, as creating a flawless diamond is still not as valuable as having a natural A level or flawless diamond of your own.
Even if you cannot afford the largest and most brilliant diamond yet perhaps, but the colored and fancy diamonds can be an inexpensive means to having a brilliant diamond. A diamond with brown or yellow can be temporarily made into a whiter stone by being coated with indelible ink. If you are inspecting a diamond, you may want to rub it also to ensure this has not been done. If it is a reputable jeweler there should be no objection to washing the diamond in front of you. All in all, you will certainly feel more comfortable with your diamond if you have given it a rigorous examinaton to the limits of your untrained eye.
Do this, and you should enjoy many years as owner of a precious diamond and a reward that will, if you have been careful in your purchase, become one of your most cherished possessions.
Derek Dashwood finds the study of diamonds and gemstones fascinating and how one small stone can take your breath away at Diamonds and Gemstones