Diamonds are naturally available in a very wide range of colours. Most people know about colourless diamonds and GIA’s colour grading system that's used to classify a diamond’s body colour…. You know D, E, F, etc. This colour grading system is only used to classify the most common diamond body colour of yellow however anytime a diamond is found in another colour 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 colourless 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 colour enhanced diamond is a 100% natural diamond that's had its colour changed. And best of all, colour enhanced diamonds come in a very wide selection of colours at very affordable prices!
A bit of history-
For many, many years it's been well known that a diamond’s colour could be “improved”. By putting a bit of coloured substance on the surface of a diamond and just like magic…. A diamond that'd a noticeable yellowish colour would change to a more attractive near colourless diamond. Unfortunately, this type of colour enhanced diamond could change back to its original body colour if this coloured substance was unintentionally removed.
In more recent years, the technology of colour enhanced diamonds has gone extremely high tech. it's now possible to completely change the colour of a diamond! These processes are considered permanent because it does remain stable when exposed to everyday normal conditions. The colour won't fade if exposed to sunlight or be washed off by harsh chemicals.
How's 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's a low body colour 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 colour but it doesn't 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 Colour Enhanced Diamonds- High Pressure / High Temperature (HPHT) treatment can improve the colour 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 colour 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 colour.
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 colour enhanced diamond. HPHT was first used to turn yellowish diamonds into more marketable fancy coloured enhanced diamonds. Now it's also used to transform some unpopular brownish diamonds into more desirable colourless coloured enhanced diamonds.
Process #2- Irradiated Colour Enhanced Diamonds- OK…. Don't start getting all excited because you saw the word irradiated! This is a 100% safe process that's very similar to what's used to preserve food by exposing it to a stream of Gamma rays. The colour enhanced diamond process is done in several different ways but the results are all the same. You start with a low colour (P, Q, R, etc.) 100% natural diamond that's already been cut and polished, then it's exposed to a stream of fast electrons. During this part of the process the diamond will turn to a very dark colour 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 colour.
Process #3- Coated Colour Enhanced Diamonds- The coating on polished diamonds refers to a thin artificial layer that alters the colour of the diamond. The coating can either be of the desired colour or can cause a coloured interference-effect. Unfortunately sometimes this process is done to deceive a buyer. it's a relatively easy process to perform, it's been around for many years (although the coatings materials are much better now). It doesn't require a lot of expensive high tech equipment. Recently, I’ve seen some pink coated diamonds on the market, they're very attractive…. and of course you'd have to purchase them knowing that they've been coated and follow your jeweller’s guidelines about owning and caring for these colour enhanced diamonds.
The coating can be applied to the whole of a diamond’s surface, just the bottom of the diamond. To a narrow zone near the girdle. A well-applied coating can change the colour by one or more colour grade. Some coatings can be removed through boiling in acid, strong cleaning solutions. Even household chemicals. Sometimes dots or larger areas of purple or blue ink are painted on the diamond to help counteract a yellowish colour. The diamond’s setting will usually cover the dots. they're difficult to see in a mounted stone.
So, is a colour enhanced diamond right for you?
Maybe…. Natural fancy colour diamonds can be beautiful but they're expensive! Colour enhanced diamonds are affordable and allow many people to own a brightly coloured diamond. Ask your local jeweller if they've any Fancy diamonds…. either natural or colour enhanced diamonds. it's always interesting. Fun, to look at something different!
Under normal wear the irradiated and HPHT colour enhanced diamonds will have no problems of the colour fading away. The only consideration will be when you need to have any type of service done on the piece of jewellery. If this type of colour enhanced diamond is exposed to excessive amounts of heat it might affect the colour. The jeweller will need to know that the diamond is a colour enhanced diamond before any work is done and then the jeweller will be able to decide on the best course of action. Colour enhanced diamonds are now also used as the small accent diamonds around a larger colourless diamond. There are many exciting pieces of jewellery available with small blue, yellow, black. Green colour enhanced diamonds.
Now that you know about colour enhanced diamonds and someone tries to sell you on what they call a natural fancy coloured diamond but it's at a super bargain price…. you'll know that something just doesn't sound right about the offer. A report from a respected grading lab should accompany all natural Fancy coloured diamonds that are marketed as natural. If you deal with a reputable company and you've been reassured about what you're buying, then you'll lessen the possibility of something bad happening to you. As with any situation involving an expensive purchase of something that not many people are well versed in, education should be an essential part of your plan. This is even more important if you plan to purchase a colour enhanced diamond.