Lab-grown Diamond Technology Process

Lab-grown diamond process
While natural diamonds can take billions of years to form, lab-grown diamonds can be made in just a few weeks through the following two processes.

High Pressure High Temperature Method (HPHT)

Using this method, a high-pressure, high-temperature environment can be created in the laboratory for synthetic diamonds, just as natural diamonds do when they are formed deep within the earth. This process results in a very distinctive crystal that, in general, resembles a combination of an octahedron and a cube with a flat base.

Chemical Vapor Deposition (CVD)

This technique is relatively new and involves breaking down the carbon-containing gas in a vacuum chamber to crystallize the carbon molecules onto the diamond seeding disc. The resulting crystals are plate-like, sometimes with graphite edges. The crystals are usually brown or yellow in color, and can become nearly colorless through subsequent HPHT treatment. The “colorless” CVD diamonds that are selected for polishing tend to have a slightly higher clarity than natural diamonds, mostly between VVS2 and VS1. Most natural diamonds in the D-N color grade range are between VS2 and SI1.

Raw, uncut CVD lab-grown diamonds are very different in appearance from natural diamond crystals. Some CVD lab-grown diamonds exhibit characteristics unique to lab-grown diamonds, such as ultraviolet fluorescence patterns. However, in almost all cases, rigorous identification requires scientific instruments and expertise that only a fully equipped gemological laboratory can provide.

Changing the color of synthetic diamonds

Although some blue and nearly colorless crystals can be produced, most synthetic diamonds grown by the HPHT process are yellow or brown in color. the HPHT process can also be used to deepen the yellow color or to significantly remove unwanted colors so that the diamonds can be graded D to Z colorless or nearly colorless.

Most synthetic diamonds grown by the HPHT process are yellow in color, but can be changed, deepened or removed by subsequent processing.

Lab-grown diamonds are identical in appearance to natural diamonds

Laboratory lab-grown diamonds have nearly identical physical and optical properties to natural diamonds. They are also very hard and are available in a wide range of colors and qualities. Like natural diamonds, they can have a high grade of cut as well as good fire, high brilliance and sparkle, they can also have a poor cut or average cut and other characteristics. It all depends on the quality of the synthetic diamond and the skill of the cutter.