HPHT vs CVD

Methods of creating lab grown diamonds:

There are two main types of processes used to manufacture laboratory grown diamonds: CVD (Chemical Vapor Deposition) and HPHT (High Pressure High Temperature). Both methods involved a diamond substrate (or a “seed”) to start the crystal blueprint needed to create the diamond. Factors such as quality, size and preparation of the diamond substrate directly correlate to the ending result of the lab diamond.

Both methods of creating lab grown diamonds are popular for different reasons – as well as manufactured in different areas of the world. The first, HPHT, simulates the natural diamond formation process by applying extreme heat and pressure in a press to the carbon molecules. The results are diamonds with a wider range of colors, but with more inclusions. This is a more energy-intensive process and is often manufactured in China. The mass production of HPHT diamonds results in smaller melee-sized diamonds that are used to manufacture grits and powders for the abrasives industry. The wide range of colored diamonds resulted from HPHT are used in jewelry as well, but with often lesser quality due to the color and clarity of the diamond. The size of these diamonds tend to often also be smaller.

HPHT Lab Diamonds:

HPHT lab diamonds should not be confused with HPHT-treated diamonds. HPHT color treatment refers to a process to enhance the color of both natural or lab-grown diamonds. Typically, it is used to turn brownish diamonds into colorless or near-colorless.

Identifying an HPHT diamond involves many specialized tools and techniques, including spectroscopy, inclusions, and certifications. 

CVD Lab Diamonds:

CVD on the other hand, is very popular in India and the United States. The process of CVD deposits carbon atoms onto a diamond substrate in a vacuum chamber, layer by layer. The chamber is filled with a gas mixture of hydrogen and methane. Under lower temperatures and lower pressure conditions, the gasses ionize and create carbon and hydrogen ions. As the carbon atoms fall onto the seed of the diamond, the crystal structure is formed and turns identical to that of a natural diamond. The result is a near-colorless or colorless diamond, with fewer inclusions and a more uniform growth pattern. The result has higher clarity and is overall a more environmentally friendly way of creating a lab grown diamond. Given the result of CVD creating a higher clarity and color quality diamond, these products are often used in high and finer jewelry pieces. Often times, CVD process can also be used to create fancy color diamonds for jewelry.

In addition to the quality of the diamond, the timing of the creation process differs significantly between the two methods, HPHT and CVD. When comparing the two, HPHT can take up to a few months to deliver the desired size, whereas CVD can take up to a few weeks.

Overall, HPHT diamonds may offer more consistent color without additional treatment, but CVD diamonds allow for finer quality control over clarity and production conditions, yielding high-quality diamonds that are indistinguishable from natural diamonds. They are used often in fine jewelry due to less inclusions and higher quality for a more affordable price, while also being environmentally friendly overall.

Please note that all of maia's lab grown diamonds are CVD.