The lowdown on lab-grown diamonds

What are lab-grown diamonds and what are they made of?

While naturally grown diamonds are formed over millions of years from carbon under high pressure and high temperature inside the Earth, lab-grown diamonds (or LGD for short) are made by human hand in the laboratory. There, in a controlled environment, diamond seeds grow to the desired size within a few weeks using highly complex technologies. The diamonds cultivated from this process have the same chemical and physical properties as mined diamonds. They are also made of 100% carbon, achieve a hardness level of 10 on the Mohs hardness scale and often even surpass their natural models in the 4C quality criteria. Since they are in no way inferior to mined gemstones (and even have some benefits by comparison), laboratory diamonds receive the same certifications as their natural counterparts from recognised institutes.

The right terminology

Synthetic, lab-grown, artificial, cultivated, simulated… numerous terms circulate in the industry for the man-made version of diamonds. However, a distinction must be made here. ‘Lab-grown’ refers to a real diamond grown in a laboratory. A rarely used name that means the same thing is the ‘cultivated’ diamond.

Other terms that do not focus on the manufacturing process but on the result are the ‘synthetic’ or ‘artificial’ diamond. Caution is advised with these descriptions. It can mean both the laboratory diamond, which has identical properties to the natural specimen, and stones that only almost match the properties. Widely used diamond imitations are, for instance, zirconia or synthetic moissanite. They also refract light, but their chemical structure is different. The term ‘simulated’ diamond almost always refers only to a diamond-like imitation.

Are lab-grown diamonds real diamonds?

Yes. Lab-grown diamonds are visually, chemically and physically completely identical to mined diamonds. They are not imitations, but real diamonds. Nevermined diamonds are guaranteed to be exclusively lab-grown diamonds with characteristics 100% identical to naturally grown diamonds.

How can you tell that a diamond is lab-grown?

Whether a diamond has been grown naturally or in a laboratory is indistinguishable to the naked eye. Experts also need special tools for this. Cultivated gemstones can be identified using the unique laser engraving on the girdle, i.e. on the edge of the stone. The way the carbon was incorporated into the diamond lattice also indicates whether the stone was made in a laboratory or not. Diamonds produced in the HPHT process, for example, have a crystalline, cuboctahedral shape, while CVD diamonds are more like a disc due to the starting material. The rough diamonds extracted therefore differ in shape from natural rough diamonds. Nevermined diamonds from 0.5 carats upwards also always come with an official certificate of authenticity from one of the most recognised laboratories in the world, the GIA (Gemological Institute of America) or the IGI (International Gemological Institute).

How are lab-grown diamonds made?

One of two processes is usually used to produce lab-grown diamonds: the CVD process (‘chemical vapour deposition’) or the HPHT process (‘high pressure high temperature’). Both processes are fundamentally different. Small, thin pieces of diamond known as ‘seeds’ are used as starting material for the CVD process. Larger stones can grow in the vacuum chamber under specific process conditions. Lab-grown diamonds from Nevermined are grown exclusively using the CVD process.

The CVD process for lab-grown diamonds

Chemical vapour deposition is the more recent development of the two aforementioned processes in diamond production. In the CVD process, diamond seeds are placed in a chamber first of all. The seeds themselves are made of diamond which is also grown in the laboratory. The chamber, which is in a vacuum, is flooded with hydrogen. With the help of microwaves, energy is added to the hydrogen gas, igniting a plasma. In simplified terms, a plasma is a mixture of particles that can be thought of as a fourth state of matter (in addition to solid, liquid and gas). Further gases such as methane and other additives are subsequently added to the plasma. In this process, the plasma heats the seed to a temperature of up to 1,000 °C. The high temperatures that arise in the chamber cause the chemical compounds of the added gases to break down. This releases carbon – the material diamonds are made of. The carbon particles now settle on the surface of the seeds and allow the diamond to grow, atom by atom, layer by layer. Diamond manufacturers are walking a physical tightrope here, as they have to carefully balance temperature, pressure and gas composition in their vacuum chamber. Fluctuations could affect the growth of the diamond, its clarity or its colour. If the complicated undertaking is successful, cuboid rough diamonds are created within a very short time. They are then processed and polished like natural specimens.

The HPHT process for lab-grown diamonds

When using the high-pressure, high-temperature process, a hydraulic press is used to mimic the conditions under which natural diamonds are formed inside the earth. Here, too, diamond seeds are initially inserted into a specially developed machine that is capable of generating extremely high pressure. Its chamber is heated to temperatures of up to 3,500 °C under up to 60,000 times the atmospheric pressure. Inside the capsule, a high-purity carbon starting material (such as graphite) dissolves in a flux of molten metals. This lowers the temperature and pressure and releases carbon atoms from the starting material. The carbon atoms migrate through the flux towards the cooler diamond seed. They precipitate upon it – and the laboratory diamond begins to grow. Within a few weeks, diamonds are created in this way. Adding a catalyst can accelerate the process and also means less pressure (‘only’ around 100,000 times atmospheric pressure) and lower temperatures (up to 2,000°C) are required. The largest diamond produced in the laboratory to date using the HPHT process was grown at the end of 2021 and weighs around 150 carats.

What quality criteria do lab-grown diamonds meet?

The ‘4C’ are criteria that define the quality and value of a cut diamond. They are derived from the first letters of the criteria: Carat, Colour, Clarity and Cut. Naturally grown diamonds have always been assessed according to these criteria and receive a corresponding certificate, for instance, from GIA or IGI. Since lab-grown diamonds are physically and chemically identical to natural diamonds, they are evaluated using the same criteria. Only the note in the certificate stating that the diamonds have been grown indicates the difference.

Carat, abbreviated as ‘ct’, refers to the weight of a diamond. One carat always corresponds to exactly 0.2 grams. The value of a stone tends to increase with its carat number.

Colour, the colour of a diamond, is indicated on a scale from D to Z. It is one of the most important criteria for determining quality. D represents ‘colourless’ and Z ‘light’, which means that the stone has a slight colouring. The further forward a diamond’s colour is on the colour scale, the more valuable it is. The colour rating does not refer to stones that have been deliberately grown in colour, which are known as fancy colour diamonds. With fancy diamonds, colour tinting is intentional. Fancy diamonds may be produced in a variety of colours, from yellow, orange and red to blue, green and black. Nevermined’s cultured diamonds, used in the mandana collections, are all in the ‘colourless’ range, i.e. with category F or better.

Clarity, the purity of a diamond, describes the amount of inclusions. If no or only surface blemishes can be detected under 10x magnification, a diamond is said to be flawless (grades F and IF). At grades VVS1 and VVS2, the stones have minimal inclusions that are barely visible to experts even at 10x magnification. For gemstones with clarity at grades VS1 and VS2, small inclusions can be detected at 10x magnification. At all grades above this (i.e. SI1 or poorer), inclusions are visible under 10x magnification (SI1 and SI2) or even with the naked eye (I1 to I3). The fewer inclusions a diamond has, the more valuable it is. Inclusions can also occur in lab-grown diamonds. However, Nevermined diamonds in mandana jewellery are always VS2-grade quality or higher.

Cut is the most important criterion when it comes to the brilliance of a diamond. Often the word ‘cut’ is also synonymous with the shape of the diamond. In the case of the 4C, however, the cut is about the quality of the cut, i.e. the symmetry, proportions and polish of a diamond. A perfectly cut diamond ensures maximum brilliance, reflecting incident light perfectly. If a gemstone is cut too deeply or too flat, the incident light is lost on the side facets, affecting the brilliance. The quality levels range from ‘Ideal’ to ‘Excellent’, “Very Good’, ‘Good’ and ‘Fair’ to ‘Poor’.

Lab-grown diamond vs. mined diamond – what are the differences?

Lab-grown diamonds and mined diamonds are the same in many ways – but they differ in some fundamental aspects. The way the diamond is extracted has a huge impact on its environmental footprint. Lab-grown diamonds are therefore much more sustainable than mined diamonds, both environmentally and ethically. In addition, lab-grown diamonds can be sold much cheaper – especially as they can be specifically produced in the highest quality grades.

Why are lab-grown diamonds more sustainable than mined diamonds?

Mining diamonds is associated with countless negative environmental impacts, ethical issues and economic challenges. To access natural diamonds in open-pit or underground diamond mines, tonnes of earth have to be moved, which can cause soil erosion. In contrast, to make lab-grown diamonds, no rainforests need to be cleared, no arable land must be rendered unusable, and no water resources are polluted. Lab-grown diamonds from Nevermined also produce lower amounts of CO2 in both their creation and transport, leaving a smaller carbon footprint. They are entirely free of inhumane working conditions or social conflict. In short: the production of diamonds in a laboratory can avoid almost all the negative impacts of mined diamonds without losing quality or increasing the price. Read more here:

Are lab-grown diamonds cheaper?

Lab-grown diamonds can be sold cheaper than mine diamonds – despite the same quality. There are many reasons for this. Firstly, diamond mining in open-cast or underground mines is associated with extensive mining processes, high personnel costs and complex logistics. On average, over 200 tonnes of earth have to be moved to produce a single carat of mined diamond. None of this is required for lab-grown diamonds. Moreover, diamonds from laboratory production almost always result in the highest category of clarity, which rarely occurs in nature. Just 1% of the diamonds mined are of the quality required for the jewellery industry. Meanwhile, the CVD process can provide almost all of the stones needed for exclusive jewellery under controlled conditions. This has a very positive effect on the price for end consumers. While mined diamonds often justify their high price by scarcity and rarity, at Nevermined, our aim is the exact opposite. We want to contribute to the democratisation of luxury by making genuine diamonds of the highest quality accessible to next generation customers.

Do diamonds from the laboratory also have drawbacks?

Compared to mined diamonds, lab-grown diamonds have few drawbacks. Nevertheless, we think it’s important to mention these, too: mined diamonds are still widely used as an investment product to obtain value in a very small space. This function does not (yet) apply to lab-grown diamonds. Grown diamonds also have a different history from mined diamonds. Although lab-grown diamonds have a more ethical background, for some people, there is value in the appeal of carrying something that has been shaped over millennia by nature itself. An exotic place of origin is often perceived as romantic. Mined diamonds pride themselves on being a scarce, difficult to obtain and very rare resource, which is not true of lab-grown diamonds – on the contrary. We want to consciously counteract this movement in favour of the environment.

Jewellery sector vs. industry – where are lab-grown diamonds used?

Lab-grown diamonds are primarily used in two areas: in the jewellery sector and in industry, for instance, in the production of microelectronics or in laser processes. LGD have been used for the latter purpose for a long time – decades to be precise. It took time before lab-grown diamonds could be produced in a higher quality that met the standards of the jewellery industry. Nevermined has chosen to produce lab-grown diamonds exclusively for the jewellery industry. For our mandana jewellery collections, we grow only the highest-quality diamonds in all 4C categories.