You have probably heard about diamonds, lab-grown diamonds, and even moissanite, or at least come across some news about them online. You may have read a thousand times that diamonds are mined from the Earth, but when it comes to lab-grown diamonds, you might simply imagine them being made somewhere inside a laboratory.
In reality, the process is not quite what the name might suggest. The manufacturing of laboratory-made diamonds is an industrial procedure involving the employment of sophisticated technology to cultivate diamonds under strict control. Thus, the laboratory-made diamonds have become a viable alternative to diamonds in the jewelry market because people can have an additional choice when purchasing a diamond.
One should remember one thing, though. Laboratory-made diamonds are created using two sophisticated technologies called CVD and HPHT. Let us discuss these technologies and see their features, differences, and possible ways to choose a superior technology for creating high-quality laboratory-made diamonds.
What Is CVD - Chemical Vapor Deposition?
There are various technologies available for manufacturing diamonds synthetically in laboratories, and one such technology is CVD (Chemical Vapor Deposition) Technology. In this process, diamond chips or diamond seeds are first placed inside the reactor.
Following this, the carbon containing gases such as methane and hydrogen are added into the reactor. Because of the presence of microwave energy in the reactor, the gas is broken down to plasma, and the carbon atoms are released. The deposition of carbon atoms takes place on the diamond seed to form a diamond crystal.
Thus, this technology utilizes the conversion of a carbon-based gas into plasma in the reactor. Next, plasma breaks down the gas molecules and liberates carbon atoms, which are deposited on the diamond seed and form a diamond crystal one layer at a time. CVD is carried out under low pressure and at temperatures ranging between 700β1,200Β°C.
What Is HPHT - High Pressure High Temperature?
HPHT means High Pressure High Temperature, which is a technology that was developed to reproduce natural conditions for growth of diamonds. The technology utilizes very high pressure, very high temperature, carbon material, and metallic solvent or catalyst. In such conditions, carbon becomes dissolved in the liquid metal and starts moving to the tiny diamond crystal, where it crystallizes and thus forms diamond crystals.
HPHT diamond production involves special high-pressure equipment that is able to generate about 5β6 GPa of pressure and 1,300β1,600Β°C of temperature. The diamond crystal grows on the seed and produces high quality single crystal diamonds that can be used in jewelry fields.
CVD vs HPHT β The Main Difference
| Feature | CVD | HPHT |
| Full name | Chemical Vapor Deposition | High Pressure High Temperature |
| Environment | Gas plasma | High-pressure, high-temperature environment |
| Pressure | Relatively low | Extremely high |
| Temperature | ~700β1,200Β°C | ~1,300β1,600Β°C |
| Diamond seed | Diamond plate | Diamond seed |
| Carbon source | Usually methane | Solid carbon |
| Catalyst | Usually not required | Usually a metallic catalyst |
| Growth process | Layer by layer | Crystal growth from a solution |
| Equipment | Vacuum/plasma reactor | High-pressure press |
| Impurity control | Highly controllable | Depends on the growth system |
| Typical characteristics | Layered/planar growth features | Metal inclusions may occur |
* Shop lab-grown diamonds in our collection to compare different stones and find the right diamond for your budget.
There is no conclusive answer regarding CVD and HPHT processes in terms of which one is superior. They can create gemstones of a high standard and the process of their formation does not affect their quality and price.
If you choose your diamond, then you should not necessarily pay attention to whether it was created by CVD or HPHT process, because both of them can create beautiful diamonds. What matters more is the diamond appearance, cut, color, clarity, and certification. To put it briefly, the growth method tells about the diamond origin but it does not define its qualities and visual features.
