History of HPHT
The history of HPHT treatments dates back to 1955, when the General Electrical Company 1st discovered the process for creating diamonds within the laboratory. This led to the creation of HPHT process, whereby GE initial created a press where the required pressure and temperature might be maintained for the process. One factor led to a different and HPHT treatment evolved through numerous presses like the tetrahedral, BARS and finally the cubic press. What began as an experiment for diamond color modification in artificial diamonds has today evolved into usage for natural diamonds also.
Usage of HPHT Diamond Enhancements HPHT treatments primarily serve 2 functions
?Creation of artificial diamonds
?Color modification in natural diamonds
Creating artificial diamonds: To obtain artificial diamonds, carbon is put within a grapite capsule. A seed is then inserted into this capsule and a catalyst is added. The diamond grows on the seed whereas the catalyst allows the crystallization to require place.
Color modification: Completely different sort of diamonds react differently when exposed to HPHT treatments and a vary of colors are obtained. For instance, diamonds containing aggragated nitrogen, when exposed to HPHT will cause it to become single substitution nitrogen. In such cases, diamonds having green, orange and yellow hues will be created. In diamonds where nitrogen is negligible, the method is typically used to supply colorless diamonds. Therefore brownish diamonds when HPHT processed can obtain a colorless hue. A light pink color could additionally be obtained in some cases. In case of diamonds with negligible nitrogen and presence of boron, HPHT will alter the color. Therefore brownish diamonds will lose the brown tone and boron can make the stone bluish in color.
Popular presses used for treatment
Belt presses: This was the initial type of press used for treatment. Here pressure is formed by the usage of 2 high strength pistons that provide equal pressure in opposing directions on a sample. A series of rings surround the sample in order to contain the pressure.
Torid press: During this method, the 2 pistons apply pressure in an exceedingly single vertical direction.
Cubic press: This uses many pistons that provide pressure from completely different directions. It's also known as a tetrahedral press.
Procedure of HPHT
If a client intends to convey diamonds for this treatment, the subsequent procedure is used,
?The stone is 1st inspected by diamond experts for cracks, fractures etc. Stones also are subject to chemical analysis using scientific equipment. Once it is confirmed that the treatment can be undertaken, the same is informed to the customer.
?Relying upon the properties of the stone, the color that may be obtained when treatment is deciphered and the customer is informed concerning the same.
?Pressure of over 1,000,000psi is applied by placing the stone in an inside pressure medium that distributes the pressure on the complete diamond equally.
?The internal pressure medium is placed into a heat generating sleeve where temperatures start at 1800 degrees centigrade.
Pricing of treatments: Price for these treatments varies with the scale of the diamond. Additionally the overall number of stones given and additional services like repolishing are charged extra. Whereas these treatments are expensive,
Organizations and HPHT
Because HPHT is controversial, totally different bodies follow different pointers for HPHT. As per the Federal Trade commission, HPHT treated diamonds should be disclosed to the user. General Electrical follows this norm and all diamonds that are HPHT treated are laser inscribed with the terms 'HPHT PROCESSED', IRRADIATED. If GIA notes diamonds to be HPHT treated, it additionally specifies them as 'HPHT ANNEALED' or 'Artificially Irradiated'. Such details are displayed prominently on the grading report below 'origin' within the 'color' section of the report.
Execs and cons
The HPHT treatment of diamonds is a controversial issue as a result of it has each blessings and disadvantages. These are more discussed as under.
?The treatment is permanent and diamonds are stable in the conventional conditions of wear and care.
?It can dramatically alter the colour of brownish diamonds to create it more appealing. Light-weight brown color diamonds will be rendered virtually colorless using this process.
?The method causes surface graphitization and therefore the diamond desires to be polished to get rid of it.
?It is tough to differentiate between regular natural diamonds and HPHT treated diamonds.
?It will cause marginal weight loss during a diamond.
?It can scale back the clarity of the stone.
As HPHT has become a lot of commercially on the market, today there are various ways on the market to detect if your stone has been HPHT processed or not. At the fundamental level diamonds over 0.five carat will solely be HPHT treated. A trained gemologist may use equipment like the SSEF spotter and crossed polarization filter to detect the same. DiamondSure is additionally used to separate cape diamonds from the rest. At the following level FTIR and UVVIS spectroscopes are used and synthetic and PT treated diamonds will easily be identified ere. Besides this, renowned laboratories have several alternative proprietary procedures that they use to spot such diamonds.
With all refined equipment it continues to be difficult to detect HPHT processed diamonds at many instances. It's so necessary that you purchase diamonds from a trusted vendor on-line or offline. Diamonds accompanied with a certificate from a reputed laboratory like GIA conjointly guarantee that diamonds are completely natural. You'll additionally select signature or prime of the road branded diamonds to shield yourself. Finally, if you cannot afford GIA stones, create positive to choose a diamond that's in the course of a certificate from a renowned laboratory.