Shopping for a lab created diamond can be confusing when terms such as CVD and HPHT appear on grading reports and product listings. Both methods can produce real diamonds, but use a different technology to form them in a controlled environment.
Understanding the difference between CVD and HPHT can help buyers to compare diamonds confidently instead of assuming that one manufacturing method creates better diamonds than the other.
CVD stands for Chemical Vapor Deposition, while HPHT means High Pressure High Temperature. Both processes create crystals with the same structure and appearances as diamonds found in nature, but have a different origin. For most jewelry buyers, the cut, color, clarity, carat, certification, and price will be more important than the manufacturing method, but knowing the difference can be beneficial when trying to understand a grading report and ask good questions before buying.
How To Make CVD Diamonds
CVD diamonds are formed when a chamber with a tiny diamond seed is filled with carbon-rich gas such as methane. The gas is ionized with energy which causes carbon to deposit on the seed and form a bigger crystal.
The formation happens under reduced pressure and manufacturers can control the process to create a desirable outcome. This is a well-established technology for growing gem quality man made diamonds.
Some types of CVD stones may need additional treatments to alter their color after formation is complete. A grading report can be helpful in finding out more information about the manufacturing process and quality of the diamond.
How To Make HPHT Diamonds
The HPHT technology imitates the natural formation of a diamond by subjecting a diamond seed and a carbon source to high pressure and high temperatures until a bigger crystal is formed.
HPHT method was the first technology to create diamonds artificially and has been further advanced to include ways to change the color of some diamonds. This method is also used during the manufacturing process of some CVD diamonds.
Difference Between CVD and HPHT in Appearance
To the untrained eye, there is very little if anything that can suggest whether a diamond was formed with the CVD or HPHT method. Both can create beautiful stones with desirable qualities such as outstanding brilliance and clarity when cut and polished properly.
Specialized equipment may be needed to distinguish between the two as the growth patterns may be imperceptible to most people. Instead of focusing on the manufacturing process, buyers should be comparing the quality and value of the diamonds. Characteristics such as cut, clarity, color, carat weight, certification, and price will help in comparing between two lab made diamonds.
A good cut is vital to bring out the beauty of a diamond and a well cut CVD stone may look better than an HPHT diamond with a poor cut and vice versa.
Difference Between CVD and HPHT for Buyers
Neither of the two methods is better compared to the other. Buyers should compare individual diamonds and think about what they want instead of choosing between them based on manufacturing process alone. Consider the grade, cut, clarity, color, carat weight, price and overall appearance. Seeing videos or photos of the diamond can be a good way to obtain more information and assess value. In the case of an engagement ring or other jewelry, the durability of the stone is also important, but both methods can create a long lasting and beautiful accessory.
Does the Difference Between CVD and HPHT Affect the Price?
The prices may vary depending on the manufacturing process, but other characteristics such as carat weight and clarity also affect the cost. The cut, color, clarity, carat weight, certification, dealer markup, and supply and demand can determine the final price once the diamond has been mined or grown. Comparing similar grades and sizes is important when trying to establish whether one option is better than the other.
FAQs
Is CVD a real diamond?
CVD is a process that creates real lab made diamonds instead of a diamond simulant such as cubic zirconia.
Is HPHT better than CVD?
Not necessarily as the grade and quality of the diamond will determine a lot about its value and appearance.
Can you see whether a diamond is CVD or HPHT?
It would be difficult to establish the difference between the two visually. A gemological laboratory will need to carry out specialized tests to determine the growth pattern of a particular diamond.
Are lab grown diamonds durable?
Yes, both HPHT and CVD diamonds will have the same durability as mined diamonds and will be suitable for everyday jewelry.