Synthetic or artificial diamonds are made in laboratory conditions that mimic the natural environments or conditions that aid diamonds to develop in the Earth. Henceforth, they are generally called lab-created diamonds. Unlike diamond simulants, those that are certified as “lab-grown” are no imitation diamonds. More than just the physical resemblance, the similarity of synthetic diamonds also extends to the chemical and optical properties of diamonds that are mined.
How are Artificial Diamonds Grown?
The advanced technology available in modern-day laboratories has made artificial diamonds superior and more eco-friendly than natural or mined diamonds. To extend the basic notion of making lab-created diamonds, it is done by placing a diamond seed into a heated pressure chamber. The specialized chamber simulates the conditions in which diamonds form naturally. Crystallization happens to allow the gemstone to fully develop within 6 to 10 weeks. After that, the gem is cut into shapes, polished, and then graded by world-famous laboratories that certify natural diamonds.
For instance, GIA has grading laboratories situated in many countries and their standards are widely practiced and trusted in the gems and jewelry segment. Yet before that, there comes a few technical processes commonly used to produce artificial diamonds in laboratories. Below is a quick look at the different lab processes.
Chemical Vapor Deposition
Abbreviated as CVD, this process is used not only to create synthetic diamonds but also to make semiconductors and optics. It makes use of extra-pure carbon-based gasses, like methane to name one, inside a controlled chamber. The gasses are heated inside the equipment until they break apart in a way that it allows for the separation of the carbon atoms inside the gas. The small carbon atoms fall onto the substrate of a diamond and build up layers, and this, in turn, produces an uncut crystal diamond. The CVD process takes 6 to 10 weeks and yields Type IIa diamonds.
In the recent past, research pertaining to this process has gained in terms of popularity so that its modified versions are being used now. For instance, the modified processes of chemical vapor deposition vary in the ways in which it initiates chemical reactions. Some of the variations of CVD comprise low-pressure chemical vapor deposition, ultrahigh vacuum CVD, plasma and microwave plasma-enhanced CVD, etc.
High Pressure High Temperature
The High Pressure High Temperature (HPHP) process recreates the environment, which is found deep inside the Earth, for diamonds to grow naturally. The machines used in this process have the capacity to build up close to 60000 atmospheric pressure and 2500 Degree Celsius temperature. The growth cell, which is placed inside the HPHT chamber’s center, has the required elements to grow diamonds. That comprises a diamond seed, a highly refined graphite, and catalyst mixture that consist of powders and metals.
The catalysts within the growth cell react to the increased pressure and heat, and then changes from a solid state to molten form. The catalyst solution, in a molten form, then causes the graphite contained inside the growth cell to dissolve. The cooling process starts once the necessary conditions are met, and occurs over multiple days allowing the carbon atoms to build up on the diamond seed. Once its growth cycle completes, the cell inside the HHPT chamber is removed. Then, a new uncut diamond is extracted, cleaned, and prepared for cutting as well as polishing.
The High Pressure High Temperature process necessitates a controlled environment to create an artificial diamond. Any variance during the growth of the gemstone can impede it or create the kind of inclusions or flaws that result in diamonds that are unusable. That is why each diamond should have completed the growth cycle before an operator can even open the chamber. It is only after it is opened that one can see the rough diamond formed inside the chamber and the gem’s properties color, size, and clarity. The diamond cutting and polishing part comes later.
Three primary tools are used within the HPHT chamber to supply the necessary temperature and pressure to create artificial diamonds.
- Bars Press – Amongst the tools used to produce lab created diamonds, this one is the most effective. It makes use of a combination of inner as well as outer anvils to apply hydraulic pressure on the growth cell placed inside the chamber.
- Belt Press – This is the founding technology, which is behind the growing of diamonds. It is capable of producing several diamonds in a single cycle by making use of two anvils that press together in order to create the required pressure. It can produce gem quality diamonds but is generally used to create diamond powder and diamonds for industrial purposes.
- Cubic Press – This can be big in terms of size and makes use of 6 anvils to create the required pressure for the growth of crystal diamond. It is also used to produce diamond powder, especially for industrial applications.