BetterThanDiamond has been involved in HPHT work since 2002, when we offered our Phoenix diamond line of HPHT enhanced natural diamonds.
With our background, this page is designed to help explain what HPHT is and how it atomically improves the rare, Type IIa diamonds.
Please note that HPHT enhancement is relatively rare and is not the same as 'clarity enhanced' or 'fracture filled'. HPHT enhancement improves the diamond at the atomic level, improving color inducing bonds and results in a stronger, more perfect diamond after the process and often, D or E color.
Nothing is added to the diamond and the process is permanent and native to the diamond itself.
Pros of HPHT enhanced Diamonds:
1 - Stronger than an untreated diamond. *All* diamonds suffer stress during their trip up to the Earths surface...in fact, many don't survive the trip at all.
The HPHT process is similar to putting the diamond back into the state where it originally grew...it can relax and heal. Strain in the crystal is relieved and as a result, it comes out a stronger diamond.
The lack of internal strain (or at least, greatly reduced strain) means the crystal itself is much more perfect as compared to a non-treated mined diamond.
I should add that diamonds can and do crack during the treatment if they have many internal inclusions, so typically the clarity on HPHT diamonds is much higher than normal mined diamonds, thought that is a net positive.
2 - Purer crystal - *most* colorless HPHT treated natural diamonds are type IIa, which is a natively purer crystal than 98% of all other mined diamonds.
3 - Better pricing - typically these are brown tinted diamonds when mined, so they are not as desirable and even though they often end up as D or E color after treatment, their price can still be half of the untreated equivalent.
The brown tinting comes from atomic bonds that have been broken or strained during the stress of the trip to the surface...once you allow those to correct, the diamond becomes what it was before the trip, typically a D or E color.
1 - Only major 'con' that we are aware of is that if you go to resell, many people may snub it because it has been 'treated'. However, this is really a reaction of ignorance - nearly all mined diamonds for example, undergo HPHT treatment in the Earth.
Most diamonds that do not undergo this are ... yellow and as you know, yellow diamonds are only 1 in a million compared to whites. Nearly 98% of all natural diamonds are born yellow - but then during a natural HPHT treatment in the Earth, the nitrogen that creates the yellow aggregates and become's optically inactive resulting in the more typical H color diamond.