Diamond color is a primary attribute that determines rarity and cost.
With advances in technology, there are various types of treatments and enhancements that can be used to alter a diamond’s color completely. Some of these methods will permanently change the diamond’s appearance, whilst others are only temporary measures.
But the question is, why go through all the hassle? Why not buy a natural diamond in the first place and save all the trouble? Well, the reason is simple and it all points to one thing: Cost.
In this writeup, I’m going to reveal the different types of treatments that are used to enhance a diamond’s color artificially and reveal the things you need to look out for to avoid getting ripped off.
A diamond’s color – or lack of color – is one of the key attributes that determine its value and appeal.
On the GIA color scale of D-Z, diamonds with the least amount of color are much rarer in nature and fetch higher prices compared to diamonds that have yellow or brownish tints in them.
On the other hand, a richer hue and more intense color of a fancy colored diamond like blue, pink or red would be highly sought after by collectors. Not surprisingly, these are also the type of diamonds that are sold at auctions for record-breaking prices.
As an example, here are 2 cushion cut diamonds that are 0.5ct in size. The one on the left is graded by GIA as an intense purplish pink color while the one on the right is a D color.
The price for a natural pink fancy colored diamond is astronomical and would probably shock you. In fact, it’s close to a 100 times more expensive than a D color diamond of the same size!
How many people can afford that kind of money ($118,000!) for an object that’s only 5mm in size? Well, I don’t although I do hope to have that kind of spare cash lying around in future. But you get the idea, these things cost a bomb.
So, what are the other options available for average consumers to get their hands on colored diamonds?
The use of treatments to artificially enhance or generate color in a diamond is one such viable solution. In the following paragraphs, I’ll be explaining the types of color treatments that are commonly used in the industry.
In the olden times, ink staining (dyeing) is one of the most popular methods used to alter a gemstone’s appearance. People could stain their diamond with a layer of colored ink to selectively enhance or reduce its hue. Do note that most inks only provide a temporary solution and will fade over time when the jewelry is worn.
With the current technology available today, much has changed. Diamonds can now undergo a sputtering process for a thin film to be evenly deposited on the surface of the stone. Although the thickness of the thin film can be in tens of microns (about the thickness of a hair), it can completely change the diamond’s color to a uniform one of your choice.
You Can Virtually Get Any Colors Of Your Choice – Photograph Credits: Serenity Technology
For example, a sputtered pink coating can give the diamond a fancy pink appearance. If a thin layer of blue material is sputtered on yellowish diamonds, it can help to neutralize the yellowish body color and cause it to appear colorless.
Like ink staining, the downside of sputtering is that it isn’t a permanent enhancement. Overtime, the coating can get scratched and may peel away with wear and tear.
HPHT treatment is probably the most well known method to change the color of a diamond on a commercial basis. With proper control of the process, HPHT can be used to lighten the tint or saturate the existing tone of a lower grade diamond.
For example, heat and pressure treatment can turn a yellowish looking stone into a fancy colored one to increase its appeal. By making some tweaks in the process recipe, the same technique can also be used to turn brownish diamonds into colorless stones.
On a microscopic scale, subjecting a diamond to high heat and pressure will cause changes to take place within its molecular structure.
Color that was caused by structural defects could now be “corrected” due to plastic deformation and rearrangement of the molecules. In the example above, the brownish hue is removed and the treatment turns the diamond colorless.
The only real issue with this process is that the final appearance can never be predetermined with 100% accuracy. That’s why there is some risk involved here as you won’t know how the diamond will look like until the procedure has been completed.
Due to its relatively low cost operations, HPHT processes are the most common treatments seen in colored diamonds. If you intend to get a natural fancy colored diamond, make sure you check and verify that it hasn’t been heat treated previously. The best way to do this is to send the diamond to GIA for grading.
As the name suggests, the irradiation process subjects the diamond to high energy rays of radiation from sources like accelerators and nuclear reactors. With the heavy bombardment of the diamond’s crystal lattice, the carbon atoms get hit out of their original positions.
This rearrangement of the crystal lattic changes the hue of the diamond. Irradiation processes are irreversible and could also be used in tandem with HPHT via a 2 step combination process. Typically, they are used to create green, blue, brown, yellow and black color diamonds.
The setting itself can be manipulated to create a look with a specific tone to it. Simply by changing the color of the setting, you can enhance the color of light that is reflected back through the diamond.
For example, a gold setting is responsible for giving mounted gemstones a yellow hue, whilst platinum and white gold settings can enhance a colorless diamond’s appearance by making it look whiter.
Having a clever ring setting design can also make the center stone look larger and create better appeal to the jewelry piece. Check out the following fancy yellow diamond ring that I purchased for my wife.
The halo setting was selected to create an emphasis on the yellow center stone. Also, the prongs were purposely made of yellow gold to enhance the color of the center stone. If you are interested, you can read full details of the ring review here.
GIA can reliably detect artificial color enhancements in fancy color diamonds.
For the uneducated consumer, buying a colored diamond is similar to opening a can of worms. Since the majority of colored diamonds in the market are treated, you have to be extremely careful with whom you are dealing with or you will get ripped off.
In order to detect the latest treatment methods, you would need state-of-the-art equipment that your local gemologist or appraiser would never have access to. I would even go as far as to say that some major labs like EGL and IGI can also fail to detect treated diamonds.
If you want to ensure what you are buying is the real deal, you should never settle for anything less than a GIA report. While wholesalers and retailers are required by law to disclose the presence of treatments, I would never place trust in what the seller claims or say about their goods.
The reason why I recommend GIA is that they are always at the forefront of gemological research and they consistently invest in lab equipment to keep up to date with detection technology.
I want to end this article by saying that it’s OK to buy treated diamonds at lower prices although I strongly advice against it. However, it is NOT OK to buy one that is being passed off as being a natural fancy colored diamond.