A lab-grown diamond is a gem identical in chemical composition to a mined diamond but grown in a laboratory environment, rather than mined from the earth.
Lab-grown diamonds are real diamonds in every way. In 2018 the Federal Trade Commission (FTC) ruled that “A diamond is a diamond, no matter whether it is grown in a lab or comes out of the ground.”
There are two different methods used for producing lab-grown diamonds. HPHT: High Pressure High Temperature and CVD: Chemical Vapor Deposition.
HPHT is the traditional method that aims to mimic the conditions found naturally in the Earth by using large mechanical presses to apply high pressure and high temperatures to a diamond seed.
CVD, or chemical vapor deposition, is a method that involves filling a vacuum chamber with carbon-containing gas, heating the gas, causing it to decompose (?) onto a diamond seed, causing it to grow. This method uses very controlled conditions, allowing for a more precise and consistent growth.
Typical CVD diamonds are grown via a multi-step start-stop process that is repeated multiple times during the growth cycle. Between each start-stop cycle, the rough diamond is removed from the reactor and laser trimmed of inclusions and other defects. The surface is then polished and returned to the reactor.
Diamonds produced in this manner exhibit unavoidable growth lines within the diamond. Once the growth stops and then restarts, the conditions that the crystal was originally growing cannot immediately be replicated.
This change in the conditions leaves a growth interface and visible inclusions can form within these interfaces. These growth lines and inclusions negatively impact the light performance of the diamond.
As you see here, most diamonds do not have growth lines that are lined up with the table. The diamonds are cut to maximize size which puts the growth lines in varying places.
In addition to growth lines, diamonds produced using typical CVD method, often result in color grades that are subpar. The diamonds are then subjected to HPHT treatment to improve the color. Often times this color can be improved up to three grades.
Post Growth treatment is listed on the grading reports for both IGI and GIA under the additional comments section.
In addition to the technology just not being available to produce premium LGDs before Clarity, even just producing high-quality CVD goods can cost manufacturers 2-3 times more than low quality CVD.
Consequently, these diamonds command significantly different wholesale prices, leading to varying retail prices. This has lead to a significant portion of manufactures producing for speed and cost efficiency only.