Diamonds are naturally available in a very wide range of colors. Most people know about colorless diamonds and GIA’s color grading system that is used to classify a diamond’s body color… you know D, E, F, etc. This color grading system is only used to classify the most common diamond body color of yellow however anytime a diamond is found in another color like pink, blue, green, etc.; then this diamond is referred to as a “fancy diamond”.
Natural Fancy diamonds can be very expensive and many times more expensive than a similar size colorless diamond. A very good example of a Fancy diamond is the infamous 45.52 carat fancy deep blue diamond, the Hope Diamond, which is on display in the Smithsonian Natural History Museum in Washington, DC.
A color enhanced diamond is a 100% natural diamond that has had its color changed. And best of all, color enhanced diamonds come in a very wide selection of colors at very affordable prices!
A bit of history-
For many, many years it has been well known that a diamond’s color could be “improved” by putting a bit of colored substance on the surface of a diamond and just like magic… a diamond that had a noticeable yellowish color would change to a more attractive near colorless diamond. Unfortunately, this type of color enhanced diamond could change back to its original body color if this colored substance was unintentionally removed.
In more recent years, the technology of color enhanced diamonds has gone extremely high tech. It is now possible to completely change the color of a diamond! These processes are considered permanent because it does remain stable when exposed to everyday normal conditions. The color will not fade if exposed to sunlight or be washed off by harsh chemicals.
How is it done?
The desired outcome of any of these treatments is to have a more marketable diamond. A less marketable diamond would be a diamond that has a low body color or sometimes a lower clarity. The color enhanced diamond treatment companies know if they start off with a certain type of diamond and process it for a certain amount of time that they should end up with a certain color but it does not always work that way. This is a science that does require some art in their processes… the only process that gives consistent results is the coating process.
The three processes are as follows-
Process #1- HPHT Color Enhanced Diamonds- High Pressure / High Temperature (HPHT) treatment can improve the color of certain types of brown diamonds and thus increase their value. General Electric has developed a process that pretty much is a mechanical simulation of a diamond’s creation in nature. The color enhanced diamond will be heated up to a very high temperature under a very high, stabilized pressure. Faults in the crystal structure are then rearranged resulting in an alteration of the diamond’s color.
Because the conditions of HPHT are very similar to diamond’s original formation, only a well equipped lab will be able to positively identify this type of color enhanced diamond. HPHT was first used to turn yellowish diamonds into more marketable fancy colored enhanced diamonds, but now it is also used to transform some unpopular brownish diamonds into more desirable colorless colored enhanced diamonds.
Process #2- Irradiated Color Enhanced Diamonds- OK… do not start getting all excited because you saw the word irradiated! This is a 100% safe process that is very similar to what is used to preserve food by exposing it to a stream of Gamma rays. The color enhanced diamond process is done in several different ways but the results are all the same. You start with a low color (P, Q, R, etc.) 100% natural diamond that has already been cut and polished, then it is exposed to a stream of fast electrons. During this part of the process the diamond will turn to a very dark color because some of the atoms in the diamond’s crystal structure have now been dislocated and this in turn has affected the way light passes through the diamond. Next the diamond goes through a controlled heating (annealing) process, this allows some of those atoms to relocate (partially repaired) in order to obtain a desired color.
Process #3- Coated Color Enhanced Diamonds- The coating on polished diamonds refers to a thin artificial layer that alters the color of the diamond. The coating can either be of the desired color or can cause a colored interference-effect. Unfortunately sometimes this process is done to deceive a buyer. It is a relatively easy process to perform, it has been around for many years (although the coatings materials are much better now), and it does not require a lot of expensive high tech equipment. Recently, I’ve seen some pink coated diamonds on the market, they are very attractive…. and of course you would have to purchase them knowing that they have been coated and follow your jeweler’s guidelines about owning and caring for these color enhanced diamonds.
The coating can be applied to the whole of a diamond’s surface, just the bottom of the diamond, or to a narrow zone near the girdle. A well-applied coating can change the color by one or more color grade. Some coatings can be removed through boiling in acid, strong cleaning solutions, or even household chemicals. Sometimes dots or larger areas of purple or blue ink are painted on the diamond to help counteract a yellowish color. The diamond’s setting will usually cover the dots, so they are difficult to see in a mounted stone. diamond painting