What are laboratory-grown diamonds?

Laboratory-grown diamonds have essentially the same chemical, optical and physical properties and crystal structure as natural diamonds. Like natural diamonds, they are made of tightly-bonded carbon atoms. They respond to light in the same way and are just as hard as natural diamonds. The main differences between laboratory-grown and natural diamonds lie in their origin. Think of it this way: laboratory grown diamonds are like ice from your refrigerator, while natural diamonds are like ice from a glacier. They are both ice, although their formation stories and the age of each are very different.

Natural diamonds formed millions to billions of years ago in Earth’s mantle then were explosively carried by kimberlite and lamproite volcanoes to Earth’s surface, often carrying fascinating inclusions within them. Laboratory-grown diamonds appear identical to natural diamonds to the unaided eye and typically require testing by a laboratory with advanced instruments to be identified.

How are laboratory-grown diamonds made?

1. High Pressure, High Temperature (HPHT)

With this method, laboratory grown diamonds are produced using high-pressure, high temperature conditions similar to what natural diamonds experience in the earth. HPHT diamond growth occurs at pressures of 5–6 GPa (roughly equivalent to the pressure exerted by a commercial jet airplane if balanced on the tip of a person’s finger) and at temperatures of 1300–1600°C.

Lower-quality diamonds, whether natural or laboratory grown, can also be put through the HPHT process to improve color. In addition to making diamonds more colorless, this process can also be used to change the color of diamonds to pink, blue or yellow. The diamond would then be called a “treated” diamond.

2. Chemical Vapor Deposition (CVD)

This technique enables scientists to grow laboratory grown diamonds using moderate temperatures (700°C to 1300°C) and lower pressures. Carbon-containing gas is pumped into a vacuum chamber and deposits onto a diamond seed, crystallizing as laboratory-grown diamond. The eventual size of the diamond depends on the time allowed for growth.

How are laboratory-grown diamonds identified?

Laboratory-grown diamonds require advanced testing in a gemological laboratory to be identified with certainty. At laboratories like GIA, scientists and graders used sophisticated instruments to analyze diamond strain patterns, trace element composition, inclusions, fluorescence, phosphorescence and more in order to separate laboratory grown diamonds from natural. These factors are different due to the vastly different formation conditions of laboratory-grown and natural diamonds.

Are lab-grown diamonds real?

Yes. Lab grown diamonds are not simulants like CZ or moissanite. Lab-grown diamonds are not “fakes.” Aside from subtle carbon distinctions, they are chemically identical to natural diamonds. The technical difference is that they’re not billions of years old. Lab-grown diamonds are grown in factories using sophisticated chemical synthesis over a period of 1-4 weeks. Once grown, they are polished with the same tools and brought to market in the same manner as natural diamonds.

Do lab-grown diamonds look the same?

Yes. Lab-grown diamonds have identical refractive index and optical qualities. Lab-grown diamonds are even graded using the same color and clarity scale as natural diamonds. Experienced gemologists and jewelers may be able to identify characteristics that point to lab-grown origin, but in casual viewing, they are identical to natural diamonds.

Are lab-grown diamonds less expensive?

Yes. Lab-grown diamonds trade for lower prices than comparable natural diamonds. The principle of accelerating change suggests that technological improvement may ultimately make them even more cost-effective to produce. With that said, at some point, producers are likely to stabilize pricing, much like miners and sight holders have done across the natural diamond industry.