What is HPHT?
HPHT stands for high pressure, high temperature and it is a process commonly used to enhance a natural diamond's color by submitting it through high amounts of pressure and high temperatures. How it Works? There are three main press designs used to supply the pressure and temperature necessary to produce synthetic diamond: , the cubic press, the belt press and the split-sphere press (also known as "BARS"). Diamonds are placed at the bottom of the press. The internal part of press is then heated to well above 1400 °C so that it can melt the solvent metal. The molten metal then dissolves the high purity source of carbon, which is then transported to the small diamond seeds and precipitates, forming a large synthetic diamond. The BARS apparatus is by far the most efficient, compact, and, economical of all the diamond-producing presses used for HPHT diamonds. The diamond is the exact same before and after the HPHT process – nothing is added nor removed from the original stone - just pressure is added. Once the HPHT process occurs, the color of the diamond is permanent and nothing like heat, polishing or re-cutting will affect the diamond's true value or its quality. As you know, a diamond starts its "journey" from the earth's core as colorless (unless of course it is a natural fancy colored diamond). Through added pressure and heat applied to the surface, the diamond becomes yellow or brown or even green. The diamonds which are suitable for the HPHT process are typically IIa rough which are very rare – (almost 2% from the total number of diamonds globally). This is because the diamonds have to have a very high purity to survive the process. Because of this, there is a limited supply of HPHT diamonds available today on the market. The HPHT process requires large investments in equipment and very vast knowledge of how to choose the correct diamonds and how to work with them in order to get the best results. Obtaining proper certification is a must for all HPHT diamonds processed by a respectable lab. It is a very important information for the customer to have in order to properly distinguish between processed and unprocessed diamond. Dianer Diamonds Ltd offers their customers a GIA certificate for each HPHT diamond that they sell. It is truly amazing what technology has done to diamonds - whether it be from the initial mining stage to modern day enhancement procedures. Today, clarity enhanced diamonds, colored enhanced diamonds and HPHT can be almost identical to untreated natural diamonds - and they more often than not will cost a lot less as well. |
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