The HPHT process Intensifies certain colors in natural diamonds.

The HPHT process Intensifies certain colors in natural diamonds.

A number of diamond enhancement techniques have evolved over the passage of time to improve the visual appearance of diamonds and the high-pressure high-temperature treatment is one of them. The technique came into existence in the year 1950 and made the diamond industry all the more lucrative and wide-ranging. Today, it has become one of the most widely known treatment for diamonds.

What is the HPHT treatment?

HPHT is an abbreviation of high pressure, high temperature. It is a process of subjecting some specific brown diamonds to enormous amount of pressure and temperature in a laboratory controlled setting which resembles the setting of the natural environment, which produces diamonds. It is like sending the diamond back into the earth, into its womb of creation to allow it to be reborn into a much better and priceless diamond. In the HPHT process, the gemologist carefully places the diamond in a “containment cube” which is then flanked by heating mechanisms. After this the same amount of pressure, which the earth creates to form diamonds is applied to the cube by putting it in a press. It goes without saying that this process requires the involvement of sophisticated equipment and facilities which are available only at some high-technology companies and research institutes.

Diamonds can be scientifically classified into two categories: “Type I” and “Type II”. The type I are the most abundant in nature and comprises of nitrogen. The color of the type I diamond usually ranges from colorless to yellow or brownish yellow. The type II are rare in nature and comprises small amounts of nitrogen. They are mostly brown, though they can be sometimes colorless and can also be blue or gray if they contain boron.

The ideal candidates for the HPHT process are usually the type IIa and the high-clarity diamonds like VVS1, VVS2, VS1, VS2 and flawless. In the HPHT process, the type II brown diamonds can be tuned into colorless or near-colorless. Certain type II diamonds of brown-pink or brown-gray-blue type can be transformed into pink and blue respectively. Of late, the HPHT method is also being used for the treatment of some of the most common type I brown diamonds.

The HPHT is a permanent color enhancement treatment and is the only treatment available to completely transform the color of the diamond. They need no special maintenance or care to maintain the color.  

Advantages of Buying HPHT Diamonds:

  • One of the major advantages of buying HPHT diamond is that it can cost up to 75% less than the natural colored diamonds.
  • Colored diamonds are not just popular, but they are also extremely rare and expensive. Due to their exorbitant rates, their availability is limited to only a selected few. With the onset of the HPHT process, they have been made affordable to everyone.
  • The treatment is irreversible and one need not have to worry about the diamond color fading or changing (unless a different color altering treatment was done).
  • With the HPHT treatment you can obtain a large variety of colors like apple green, forest green, olive green, golden yellow, sky blue, and many more.
  • Last but not the least, the HPHT diamonds cannot be distinguished from the natural diamonds, making it look absolutely real in every aspect. They can only be differentiated via an advanced spectroscopic technique.


 Disadvantages of Buying HPHT Diamonds:

  • They haven't gone through the "maturation" process naturally, so HPHT diamonds are less desirable by many people.
  • Cheap color enhancing treatments advertised as HPHT may cause diamonds to change color after a few months of the treatment.


Posted by Roy Izakov.
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