CVD and HPHT Diamonds

CVD and HPHT are two lab-created diamond production methods that are physically, chemically, and optically identical to mined diamonds. Both methods can be used to create stunning, high quality synthetic diamonds.

Both methods grow diamonds from seed crystals using carbon atoms, which are ionized into plasma in a chamber. Over a period of weeks, small diamond crystals begin to form in the chamber.

Cost

The cost of cvd and hpht diamonds varies based on the process used to create them, their cut and clarity, the size of the gem and whether it has any metal inclusions. It is also important to consider the style of jewelry setting you want your lab grown diamond to be incorporated into.

In general, cvd diamonds are less expensive than HPHT diamonds. The main reason for this is because they are not created in a high pressure and high temperature environment, but rather through chemical vapor deposition (CVD).

CVD diamonds are formed by using superheated gas to stimulate and grow a tiny’seed’ of diamond into a full-sized gem. These are then inspected by a certified gemological laboratory for color, cut and clarity.

Unlike mined diamonds, which take hundreds of millions of years to form, lab-grown diamonds are created in a matter of weeks. This method allows them to be much less expensive than natural diamonds, and it offers a transparent supply chain.

The most common process for growing lab-grown diamonds is the high pressure, high temperature (HPHT) technique. This mimics the conditions that are found deep underground where natural diamonds are formed. These conditions include high temperatures and pressures of 2,000 degrees Celsius, which are replicated in the HPHT lab.

Another common way to create lab-grown diamonds is through the chemical vapor deposition (CVD) technique. This was developed in the 1980s and is a newer method that imitates how diamonds are formed in interstellar gas clouds.

Like the HPHT diamond process, CVD uses a small diamond seed placed in carbon, the element that makes up a diamond’s crystalline structure. The seed is then exposed to high temperatures and pressures. This is a process that can be used to make smaller diamonds as well as larger ones.

Because of their lower costs, cvd diamonds are also more readily available than HPHT diamonds. This is particularly true for those who are on a tight budget.

However, this does not mean that cvd diamonds are inferior to HPHT diamonds. In fact, a CVD diamond can be just as beautiful and sparkly as an HPHT diamond.

Color

Lab grown diamonds are created in laboratories using one of two methods: HPHT or CVD. These man-made stones are created with the same physical and chemical properties as natural mined diamonds, with the exception of color. They are eco-friendly and almost 40% less expensive than natural diamonds, making them a great option for your engagement ring.

HPHT stands for “High Pressure, High Temperature,” and it is the primary process used to create lab grown diamonds. It recreates conditions that formed natural diamonds below the surface of the earth by introducing extreme pressure and heat onto a small seed crystal. These forces cause carbon atoms to move from the metallic flux to the seed crystal where they begin to grow into a full diamond.

The HPHT method has been around since 1954 and is widely regarded as the gold standard of lab grown diamonds. It has the ability to produce very high quality diamonds, even ones that are difficult to grade.

In addition to the HPHT process, some labs have started using the CVD (Chemical Vapor Deposition) method of growing diamonds, which is less expensive and more efficient than the HPHT method. However, it has a few disadvantages when compared to the HPHT process.

First, it is more difficult to distinguish between HPHT and CVD diamonds. Because both methods are based on a similar process of replicating geological conditions to produce diamond crystals, identifying the difference between the two can be challenging.

Besides the fact that the two processes produce very different diamonds, they also vary in their color characteristics and clarity. This can make them a confusing choice for buyers, and it is important to be aware of the factors that impact these differences.

For instance, an HPHT diamond can be yellow or brown, whereas CVD is much more likely to produce white or colorless diamonds. The GIA has published indicators for differentiating these diamonds.

Another way to tell the difference between an HPHT and CVD diamond is by looking for upward growth striae. This is a unique feature of CVD diamonds and is very difficult to identify without gemological instruments.

Clarity

The process that is used to create a lab-grown diamond will determine the quality of the gem. Two methods are commonly used: Chemical vapor deposition (CVD) and high pressure, high temperature (HPHT).

CVD is a process that uses a chamber to heat up the diamond seed to about 800 degrees celsius. As it gets hotter, the seed begins to grow layer by layer.

During this process, the carbon gases in the chamber are broken down to release pure carbon pieces that can then combine with the diamond seed. The process then continues until the seed crystallizes into a diamond.

This can sometimes lead to vacancies where carbon atoms are missing, causing the diamond to become colorless. However, this doesn’t always happen in CVD.

Another way to tell a lab-grown diamond from a natural one is by looking at the shape of the stone. Natural diamonds can have an octagonal or round shape, while CVD diamonds can be square or rectangular in shape.

The shape of the stone also has a direct impact on the clarity. A round diamond is usually more clear than a square diamond because it doesn’t have a lot of striations.

Additionally, it’s important to note that lab-grown diamonds often exhibit metal inclusions in their structure. This can help scientists to identify the stone as lab-grown, because naturally formed diamonds rarely capture metals during formation.

These metallic inclusions can make a diamond magnetic, which is an indicator of its laboratory-made origin. This is an important factor for consumers who want to know whether a lab-grown diamond is real or not.

In addition to this, there are some other ways to distinguish a lab-grown diamond from a diamond mined in the earth. These include the presence of boron impurities and a blue hue.

This blue nuance is not a problem with HPHT diamonds, but it’s an issue with CVD diamonds because it can cause the stone to have a fuzzy appearance. This can be difficult to distinguish from a natural diamond using your naked eye, but it’s something that gemologists can detect with advanced techniques like GIA and IGI.

Shape

While lab-grown diamonds share the same physical and chemical composition as Earth-mined diamonds, they differ in specific characteristics. This is why only qualified gemologists can tell them apart using special equipment and techniques.

There are two main types of lab grown diamonds, cvd and hpht, each of which has its own unique shape and growth process. It is important to understand the difference between these two types of man-made diamonds so you can make the best choice for your engagement ring or other jewelry piece.

CVD, or chemical vapor deposition, is a diamond manufacturing method that uses carbon gas to create diamond crystals. This procedure mimics the natural diamond-making process, which is why a CVD diamond has the same look and quality as an Earth-mined diamond.

To start the CVD process, a small diamond seed is placed in a chamber and heated to 800 degrees Celsius. This temperature melts the diamond seed and allows it to assemble into a diamond. The chamber is then filled with a carbon-rich gas combination, such as methane and hydrogen. The gas mixture is ionized into plasma by microwaves and lasers, which breaks down the molecular bonds in the gas and allows pure carbon to adhere to the diamond seed.

Once the carbon has accumulated to a certain level, it is allowed to cool down to complete the process. A diamond that is created through this method typically has a cubic shape with growth occurring only in one direction.

On the other hand, HPHT diamonds are shaped into a cuboctahedron and grow in multiple different directions. This process replicates the conditions that formed natural diamonds underground and gives them a more authentic look.

In addition to their different growth patterns, HPHT diamonds also have a fluorescence color that is more noticeable when exposed to short-wave UV light. This color is similar to a natural diamond, but it is more prominent and stands out from the surrounding diamonds.

Another characteristic of HPHT diamonds is a lack of strain lines or blemishes in their internal graining pattern. This can be difficult to determine by the naked eye, but a trained gemologist can identify these differences. The GIA recently published a guide on how to spot these differences in HPHT diamonds, which is helpful to consumers and jewelers alike.

CVD and HPHT Diamonds