Color Enhanced Diamonds

Color enhanced diamonds are an alternative to Natural Fancy Color diamonds…. color enhanced diamonds start out as “ugly ducklings” that have been altered from their original color.

The color enhancements make some diamonds more marketable and for the most part the enhancements are considered permanent. Many of the color enhanced diamonds that I’ve seen over the years were very attractive and were also offered at pretty attractive prices!

fancy red diamonds

This little 0.95ct natural Fancy Red Diamond (not a color enhanced diamond) sold at a Christie’s auction for a cool $1 million per carat ($950,000 total)…. you could add a Natural Fancy Color diamond like this to your wish list!

Most Common Color Enhanced Diamond Treatments

#1 – I hate using this term, but here goes…. Irradiated Diamonds… still there?

You didn’t go running off screaming… “Is he crazy!!!? A diamond that’s been nuked!”…. are you still there??…. OK, good! Let’s continue.

This color enhancement 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 exposed it to a stream of fast electrons, this is a similar process that is being used in preserving food.

During this part of the process, the color enhanced diamond will turn to a very dark color because some of the atoms in the diamond’s crystal structure have now been dislocated (bumped out of place) and this in turn has affected the way light passes through the color enhanced diamond.

Next, the color enhanced diamond goes through a controlled heating process, an annealing process, this allows some of those atoms to relocate in order to obtain a desired color.

The 4 color enhanced diamonds shown above have had this treatment. This is a totally safe process and the color enhanced diamond’s new color will be considered permanent. An “ugly duckling” of a low color diamond is able to be transformed into brilliant color enhanced diamonds featuring hues such as canary yellow, pink, blue, gold, green, cognac, orange, and black.

color diamonds


High Pressure/High Temperature (HPHT) treatment can improve the color of certain types of brown diamonds and thus increase their value. In the mid-90s General Electric developed a process that duplicated the conditions of diamond’s creation in nature. The color enhanced diamond will be heated up to a very high temperature under a very high, stabilizing pressure. Faults in the crystal structure are then rearranged resulting in an alteration of the diamond’s color.

Because the conditions of the HPHT process 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 diamonds, but now it is also used to transform some unpopular brownish diamonds into more desirable colorless diamonds.

rare diamonds

#3 Coatings

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. These color enhanced diamond coatings are not permanent and they are sometimes done to deceive a buyer when the treatment is not disclosed.

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 the jeweler’s guidelines about owning and caring for these type of color enhanced diamonds.

These coatings can be applied to the whole of a color enhanced 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 color grade. Some coatings can be removed through boiling in sulfuric acid or hydrofluoric acid.

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.

The coating can usually be removed with water or cleaning solutions. This last process is definitely performed to deceive someone and is not encountered in a reputable local jeweler or one of the large online diamond sellers.