High Pressure High Temperature (HPHT) processing is a new technology that makes permanent color change in diamonds possible. It reproduces the same environment found in the earth that cause color in diamonds, nothing is added or removed from the diamond. When successful, the result is a diamond that is indistinguishable from any other diamond. Of the infinite possible outcomes, the most coveted are the exotic pure fancy colors.

The process to achieve the temperature and pressures required is highly specialized and very expensive. Finding the diamond that possesses the rare elemental make up to yield a satisfactory result is painstaking, and discovering one that yields a truly magnificent color like this fancy intense greenish blue, is extremely rare and very exciting.

There are other methods for changing a diamond’s apparent color which are not permanent or durable. They are sometimes advertised with phrases like: “Ion Fused” or “Enhanced”. Unlike these “enhancements” the color a diamond has after the HPHT process is permanent and irreversible, indistinguishable from a diamond mined from the earth with the same fancy color.

The Gemological Institute of America’s Gem Trade Laboratory will not assign a fancy color grade to a diamond unless it was mined from the earth a fancy color or a permanent process like HPHT was used to cause fancy color. The reason a diamond in the earth has fancy color is from exposure to high pressure and temperature deep in the earth’s crust and many times exposure to elements emitting natural radiation. The HPHT process combined with radiation reproduces this environment causing diamonds to have fancy color in the exact same way. It produces the same permanent results and is way the GIA will perform the highly coveted Colored Diamond Grading Report for diamonds with fancy color as a result of HPHT process.

HPHT diamonds have the same beauty, permanency and durability as all diamonds and when the result is a pure fancy color they are a true wonder of great rarity.

The rarest fancy color for diamonds is red. September 2017 the largest to date (2.11 carats) red diamond ever produced by the Rio Tinto’s Argyle mine in Australia was unveiled and is being offered for tender, (with a GIA fancy color diamond grading report stating the color is fancy red with a clarity of VS2). Experts and speculators say it will sell for 5 million per carat making the Argyle Everglow fancy red color diamond the most expensive per carat gem ever sold.

The next rarest fancy colors for diamonds are blue followed by green then violet then orange then yellow, completing the 6 spectral colors.

In the realm of HPHT process, fancy blue color diamonds are by far the rarest color to achieve. The subject diamond has to have the rare elemental property of being nitrogen free which is less that 1% of mined diamonds.

We first learned of HPHT technology 10 years ago at an American Gem Society Conclave seminar and since, have been offering these diamonds to our customers. HPHT diamonds with pure fancy color sell for about the same as high quality colorless diamonds and compared to diamonds that are mined from the earth exhibiting pure fancy colors, HPHT diamonds are up to 100 times less expensive. This offers the diamond buyer a new and wonderful choice when selecting a diamond.

We were excited about the pink colors that were readily available from producers. Beautiful colors with full GIA documentation selling for up to 20 times less than diamonds mined from the earth pink color with the same GIA results. The only difference on the GIA report was the color origin statement. Sure, everyone would love to have $500,000 to spend on a 1 carat vivid pink diamond but many, when offered an HPHT 1 carat vivid pink diamond with the same color description on a GIA Colored Diamond Grading report for $40,000 find that choice more attractive.

With HPHT diamonds it is easier to produce the more intense stronger colors. Especially the pink colors, the green and yellow colors as well. Although rare, it is not that uncommon to produce a fancy Red color with the HPHT process. Today, to buy a 1 carat fancy red with natural color origin even with an eye visible inclusion would cost $1.5 million or more . . . To buy the same color HPHT origin (indistinguishable from natural origin) would cost around $15,000. 100 times less . . .

Over the time we’ve been selling these diamonds we have sold many pinks and even a couple of reds and seen some spectacular greens, oranges and yellows along the way but we never saw an HPHT blue even though we were told by the producers that the HPHT process was capable of producing blue colors. Their explanation was that to produce blue, the subject diamond had to be a very rare nitrogen free diamond type. Blue is by far the rarest of the HPHT colors.

Please check with us to see what HPHT diamonds we have available.  Just maybe we’ll have a rare blue one to show you!!
The ring you see here was the first HPHT blue diamond we acquired after more than 10 years of searching.  It has been sold and is no longer available.  We're hoping to get lucky and find another one soon.

Thank you for reading our blog.

The American Gem Society Certified Gemologist Appraisers at Opal Fields.