Lab-grown HPHT rough diamonds (middle)
Natural rough diamonds (right)
If you put lab-grown CVD, HPHT, and natural diamonds in front of everyone’s eyes, they are equally crystal clear, full of fire, and look exactly the same. However, natural diamonds are formed over a billion years or more, while cultivated diamonds are formed in units of days.
Natural diamonds are formed by forces deep within the young earth. The other is from a laboratory, and its chemical, physical and optical properties are basically the same as natural diamonds. However, from the name, they can all be called diamonds.
According to the U.S. Federal Trade Commission (FTC) trade guidelines for the gem and jewelry industry, a diamond is defined as a material, not a gemstone, that is composed of essentially pure carbon, crystallized in an equirectangular system of minerals.
Although the FTC mentions that diamonds are essentially pure carbon, the vast majority of natural diamonds contain traces of other elements, such as nitrogen and boron. In addition, they often contain inclusions — tiny foreign objects trapped inside diamonds that are still forming millions of years ago.
Lab-grown diamonds (commonly referred to as man-made or synthetic diamonds) entered the gem and jewelry business market about five years ago. Although they look identical to natural diamonds, they have very subtle differences that can only be detected by trained gemologists and sophisticated equipment designed for this purpose.
Before understanding lab-grown diamonds, we must first understand natural diamonds.
Natural diamonds formed as early as 3 billion years ago under extreme pressure and heat deep in the Earth. The volcanic activity brought them from the ground to the surface, and they lie in a volcanic rock called kimberlite, waiting to be mined. Of these, only about 5% of kimberlites contain enough diamonds to be economically valuable to mine.
Let’s talk about lab-grown diamonds.
In the 1950s, man-made diamonds suitable for industrial use were first grown in a laboratory. Stone-quality lab-grown diamonds first appeared in 1971, but it wasn’t until the mid-2010s that colorless lab-grown diamonds entered the gem and jewelry market in large numbers.
Today, lab-grown diamonds are produced in two ways: CVD and HPHT.
High-pressure high temperature (HPHT) diamonds are produced in the laboratory under high pressure and high-temperature conditions that simulate the formation of natural diamonds on Earth. This process produces a uniquely shaped lab-grown diamond crystal.
The chemical vapor deposition (CVD) diamond method involves breaking down carbon-rich gas molecules, such as methane, into carbon and hydrogen atoms, which are then deposited on diamond seeds to form square-shaped, platelet-shaped diamond crystals.
Regardless of the method used to grow a diamond, it usually takes less than a month for most sizes. Most CVD-grown diamonds require additional treatments, such as heat or irradiation, to enhance or change their color after cultivation.
Generally speaking, lab-grown diamonds do not weigh more than 1 carat, but with the advancement of technology and craftsmanship, larger lab-grown diamonds have appeared on the market. Many labs are also constantly breaking records for the weight of grown diamonds.