Diamonds’ Clarity Enhancement Processes

Diamonds are among the most highly priced gem stones on Earth. They are widely used as  jewelry ornaments and industrial tools. Diamonds are among the highest demanded items because of its beauty and durability. However, colorless and  flawless diamonds are extremely rare. Therefore, some diamond dealers enhance non-gem quality, highly included and/or colored diamonds to improve their overall appearance. There are several processes to enhance the clarity and color of diamonds.

The clarity of a Diamond:

The clarity of diamonds refers to the degree of the imperfections or inclusions embedded in a diamond. Inclusions can make a diamond look ugly for many reasons. These imperfections also interfere with the light that can pass through the diamond and create its sparkly reflection. If you look closely at the diamond, you can see the edges where lights reflect as it passes through the stone. Inclusions lessen the brilliance of the diamond because it restricts the light from coming through. To hide these inclusions, diamond cutters are very careful in cutting the diamonds. Usually, they cut under the bezel facets or near the girdle to hide the inclusions.

To add the market value to non-gem quality diamonds, there are several ways to enhance their clarity. Among the widely used processes are the color enhancement, the HPHT (high-pressure, high temperature) process, the laser drilling, and the fracture filling.

Color Enhancements:

One of the widely used processes to treat the clarity of a diamond is through color enhancements. These include treating the diamond using a mask or coat to polish the diamond. In this process, the diamond is coated with the matched color; usually a super thin layer of industrial chemical or a durable plastic is used. Some jewelry manufacturers use synthetic diamonds to mask a tinted area, thus giving the blemished diamond a look of a colorless stone.

Subjecting diamonds to HPHT:

Another method to enhance the clarity of a diamond is by subjecting it to HPHT. HPHT is an industrial acronym that stands for high-pressure, high temperature. During this process, the diamond, tainted or raw, is subject to a very high pressure and very hot temperature in a laboratory to create a new colored gem stone. Diamonds that appear to be colorless, yellow, pink, green, and yellowish are subjected to this process to create their color effect. This color effects also treat the clarity of a diamond. When subjected to this treatment, the blemishes of diamonds are barely undetectable.

The color of a diamond treated under HPHT is permanent as they have been under acids, ultrasonic treatment and high amount of pressure and heat. Diamonds subject to HPHT are usually more polished as a result of surface oxidation. It restores the shininess of the diamond, giving it a gleam of new look. However, since it has been polished, there is a chance that the diamond will lose some of its weight.

Laser drilling:

Another common method to restore the clarity of a diamond is through laser drilling. This is widely used method since the early part of 1960s. Laser drilling cleans the dark (sometimes brown or colorless) marks inside the diamonds. These marks are usually made of other minerals that develop inside the stone. They can be graphite (which will become diamond in hundreds of years to come), sulfide or iron.

During the laser drilling process, the laser is positioned directly at the location of the blemish. It should be precise to avoid destroying the gem stone. Laser drills are usually set at 1064 nm solid-state. The laser creates microscopic incisions to clean the imperfections. Once the laser treatment is complete, the treated diamond will be clearer to look at.

However, some experts say that laser drilling leaves empty spaces once the inclusions were removed. Just like in any filled spaces, once a certain substance was removed, blank spaces are left. These spaces leave hallow tunnels inside the gem stone which can damage its durability. This is where the next process comes in – filling those empty spaces through fracture filling.

Fracture filling:

Once the diamond underwent a treatment, especially the laser treatment to remove blemishes inside, the process leaves an empty space. This makes the diamond more fragile and less durable. Some jewelry makers and collectors even find treated diamonds to be impure and of lesser value. To take care of this concern, diamond collectors, jewelry makers and those who are in the gem industry discovered a process to fill in those hollow spaces. This process is called fracture filling.

During fracture filling process, another diamond is inserted inside each space, thus, hiding the imperfect ‘feathers’ or fractures of the gem stone. Aside from real diamonds, jewelers also use glasses, and synthetic diamonds as fillings. This is an intricate and delicate process. It requires precision and skills in diamond cutting to master this type of filling.

Once the process is finished, it will be very hard to distinguish the filling in a diamond. However, a true skilled diamond master or diamond grader can spot the difference. There are also several claims that diamonds that underwent fracture filling are not permanent and that they can be destroyed, especially when they are subject to several cleaning and immense heat.

Laser drilling and fracture filling are among the widely used processes in the market today. Although there are numerous ways to identify a clear diamond from a treated one, it is still advisable to consult an expert of these stones when you are about to buy a piece of jewelry. There are magnifying glasses used in jewelry stores to prove that what they sell are real diamonds, along with some grading companies that can provide a certificate clarifying if a diamond is treated or not.

How to find out if a diamond is enhanced in GIA reports?

Here is an illustration of how GIA address such enhancements, if any, in its grading reports for natural diamonds. Always pay close attention to the comments section .

First GIA would put a star sign next to the clarity or color (whichever is enhanced) as shown below:

Then, GIA would explain how the diamond is treated in the comments section as shown below: