What are lab-grown diamonds?

They are Diamonds for the future: affordable, sustainable and a brilliant achievement of human technology and intelligence.

What is the difference between a laboratory grown and an earth mined diamond? The answer is almost nothing in terms of physical properties. A lab-grown diamond is a diamond, with the same physical, chemical, and optical properties as a mined diamond. The only difference is their point of origin – in the ground for a mined diamond, above the ground for a lab-grown diamond – and the different impact each has on the environment and on the people working to produce them.

Even the most experienced gemmologists can have trouble telling the difference between modern lab-grown diamonds and earth-mined diamonds. Lab diamonds have the same crystal structure, chemical composition, optical properties, and physical properties as a mined diamond: both are composed of carbon atoms arranged in a cubic crystal structure.

Rather than forming in the depths of the Earth’s mantle, a lab-grown diamond is created in the controlled environment of a laboratory. The first attempts to grow a diamond go back to the 1950s, but it’s only in recent years that scientists have succeeded in creating diamonds of sufficient quality to be mounted in jewellery.


Today there are two methods of creating lab-grown diamonds.

High Pressure-High Temperature  (HPHT)

This method replicates the conditions in which diamonds were formed deep within the Earth, billions of years ago. A diamond ‘seed’ is placed in a growth cell and common graphite (carbon as in a pencil lead), is inserted on top of the diamond seed, inside a pressure cooker, then subjected to extremely high pressure and a temperature in the region of 1,500°C. In the presence of a catalyst, the pressurised and heated carbon crystallises into a diamond crystal.

HPHT is sometimes used to later improve the colour of both mined or lab-grown diamonds.

Chemical Vapor Deposition (CVD)

These diamonds are created in low-pressure vacuum plasma chamber or reactor. Thin diamond plates are placed in a growth cell and hydrocarbon gas is injected into the reactor. High power microwaves break apart the molecules of the gas, and the carbon atoms precipitate onto the diamond plates, replicating the molecular arrangement of the seed diamond slowly building up layer by layer to crystallise into diamond, thus growing the diamond, atom by atom.

The resulting CVD diamonds are often subjected to extreme pressure to ‘compress’ the diamond. This additional step improves the quality of the diamond crystal, giving the diamond better colour and light performance.

Because lab diamonds grow just like natural diamonds, but speeded up, variations will also occur in colour and clarity. In other words, not all lab-grown diamonds are colourless and flawless. It takes patience to grow a diamond and if the process is speeded up too much the diamond crystal will not be of optimal clarity. There is a physical speed limit to how fast you can grow diamonds which means it takes 7-10 days to grow a 1-carat lab diamond, and about a month to grow a 3-carat diamond.

Laboratory-grown diamonds are graded using the exact same criteria as mined diamonds (The Four C’s), and by the same independent gemmological laboratories that grade earth-extracted diamonds Do not confuse lab diamonds with cheap diamond simulants, such as cubic zirconia and moissanite.

Adamastar proudly offers only laboratory-grown diamonds in our fine jewellery. Compared to mined diamonds, our sustainably cultured diamonds have fewer impurities and fewer defects. Technically, there are different types of diamonds such as ‘Type 1’ or ‘Type 2’. The majority of diamonds are type one, ‘Type 2’ are much rarer as they are a purer diamond. Only 2% of earth-mined diamonds fall into this superior category. Lab-grown diamonds are all Type 2. This makes our diamonds whiter, brighter, and stronger than most mined diamonds.

magnicent gemstone

If you were fortunate enough to discover a rough diamond in the ground, you might assume it is just another unremarkable, irregular shaped pebble.

It has taken diamond cutters generations of experimenting and passing down the (often jealously guarded) knowledge, of the physical and optical characteristics of such an unremarkable pebble, to bring out the brilliance and fire of a polished round brilliant cut diamond.

There is a wonderful symmetry with artisans skilfully beautifying this magnificent gemstone and now, with human ingenuity, actually creating it.

A lab-grown diamond is a diamond for the future. We invite you to experience the wonder of lab-grown diamonds for yourself in an exquisite piece of jewellery from Adamastar.