I am asked frequently about hybrid diamonds, CVD diamonds, and HPHT diamonds. There is a huge surge of companies looking to capitalize on the monetary opportunities surrounding these "diamonds", without considering the best interest of the consumer. Of course, the conversation almost always leads to whether or not I sell them... but I think before I answer that question, it’s important to know the difference between hybrid, CVD, and HPHT diamonds.

 

A collection of hybrid diamond stones

The industry is still getting a hold of how to use terms like diamond as opposed to lab-grown diamond. There's no time for a breather before the next complexity comes along. Now there's a diamond hybrid and various synthetic options available. Yep. Natural-synthetic hybrid diamonds are on the market, and it's important to understand just what in the world they are so we can ensure consumers are properly educated.

Hybrid Diamond Defined

A hybrid diamond consists of a crystal core with synthetic diamond infused to the outside of the core. The outer diamond layer is bonded at the molecular level, giving the gem a higher durability factor. Diamond hybrids are VVS in clarity and DEF in color.

In other words, the simplest answer to the question of "What is a diamond hybrid?" is this: a diamond hybrid is a composite. It's part crystal - sometimes part natural diamond - and part synthetically grown. In fact, the Gemological Institute of America (GIA) identified a “0.64-carat fancy grayish-greenish blue cushion modified brilliant” as being a natural diamond with CVD synthetic diamond overgrowth.

There's that term again, CVD. It stands for Chemical Vapor Deposition. If that's confusing to you, you're not alone. Basically, in the case of the GIA-identified stone, the natural diamond contained yellow beneath its substrate. By growing a gray and blue CVD synthetic layer over the natural diamond, it combined with the natural diamond to create a new color, while adding extra weight.

This was the second such diamond hybrid assessed by the GIA. The prior diamond identified by the GIA was a 0.33-carat fancy blue from May 2017. It was also a Type IIb with a similar CVD layer. The big difference between the two diamonds is that the newer one has a much thicker CVD layer (200 microns vs. only 80).

Synthetic Diamond Defined

There are two main ways to create synthetic diamonds. The first, which we have already briefly touched upon, is called Chemical Vapor Deposition (CVD). Using the CVD process, a diamond starter seed is placed in a sealed chamber and heated to extreme temperatures. The chamber is then filled with a carbon-rich hydrogen and methane gas. This ionization breaks down the carbon gas, allowing the pure carbon molecules to adhere to the diamond seed. The carbon then slowly builds into a crystal, layer by layer. CVD diamonds typically grow within 14 days.

The second way to create a synthetic diamond is through the High Pressure/High Temperature (HPHT) method, which mimics how diamonds are made in nature. This process begins with a diamond “seed” that can be either a natural diamond or a synthetic diamond. Hydraulic pressure and a proprietary recipe of iron, nickel, and cobalt flux create an environment that encourages the starter seed to grow. 

Identifying Natural-Synthetic Stones

It's a good sign that the GIA is able to identify each of the components of natural-synthetic hybrid diamonds. While there are still indicators that signal when a diamond is synthetic, the presence of natural features as well means that testing will need to stay a step ahead. When there's a clear line of demarcation between the natural and CVD layers, identification is simpler. However, the processes that produce diamond hybrid stones will likely become better as technology advances, making synthetic signals more subtle.

Already, these hybrid stones achieve a natural photoluminescence – something that often reveals CVD diamonds. This is just another reason why the GIA assesses diamonds in such a wide variety of ways – what one testing process might overlook, another won't.

Maintaining Trust and Quality of Product

It's likely we'll continue to see diamonds that grew in the earth with lab-grown layers added over them. As always, it's of paramount importance that customers – and those who sell to them – have complete knowledge of the nature of their diamonds. This is why the team at K. Rosengart submits all melee parcels for analysis. It's still the most thorough way to ensure the quality of every diamond.

Today's consumer is overwhelmed with options. It’s important that the end user understand the difference between those options that go beyond cost. Personally, I always want to be sure clients understand that there is no resale value on hybrid and synthetic diamonds because the stones can be replicated endlessly.

One of the most alluring parts of the diamond business is the history and value behind natural diamonds, unlike synthetic diamonds produced in a matter of weeks using microwave reactors. Mass-produced hybrid and synthetic diamonds are sold at various price points based on the growers and the quality.

Trusting the company you’re buying diamonds from is the most important factor. Make sure your buying from a reputable company offering you the best quality for the best price. At K. Rosengart, we have chosen not to sell hybrid or synthetic diamonds, because we believe it would be a huge conflict of interest - one that would erode the trust of our clients and diminish the quality of our product.

 

Diamond Education Guide for Consumers | FREE PDF Download | K. Rosengart