Monday, 17 October 2016

HPHT Diamonds

Diamonds are precious stones which are found inside earth’s surface.Diamonds can also be produced inside the laboratory by using HPHT process(High pressure High Temperature) and CVD(Chemical Vapour Deposition).Such diamonds are called as Lab Grown Diamonds or Lab Created Diamonds.
HPHT Diamonds and CVD Diamonds create diamonds which are chemically, physically and optically exactly the same as mined diamonds.

HPHT is a Diamond Enchanement Process used to enchance natural diamond’s colour by making the natural diamond go through high amounts of pressure and high temperatures.HPHT Process creates diamonds that are of different colour than original diamonds.
In HPHT Process 70,000 atmospheres pressure(same pressure that is found inside mines) at temperatures upto 3,700°F.HPHT Diamonds can be used for 1)Creation of Synthetic Diamonds 2)Color Modification in Natural Diamonds.
In HPHT Process a trained gemologist places the diamond into a “containment cube” that is surrounded by heating mechanisms.Pressure is applied to the cube.By this process we get a diamond in its most mature,desirable and colourless state.Because of the high amount of pressure HPHT Colored treated diamonds are larger than 0.50 carats.The smaller diamonds cannot handle this extreme pressure and can implode.
Two main press designs are used to supply required temperature and pressure.
Belt Press:-High Pressure is created by using two high strength pistons which provide equal pressure in opposing directions.
Cubic Press:-This technique uses many pistons that provide pressure from many different directions.
HPHT can only be used on high clarity diamonds like VVS1,VVS2,VS1,VS2 and flawless.  
The HPHT diamond maturation process is permanent and irreversible.It is a permanent colour enhacement process.
The difference between a natural colour diamond and HPHT Coloured diamond can be made by freezing the diamond with liquid nitrogen.The cool diamond is excited with a laser to see the colour that appears.

A spectrometer is used to measure the difference in the light absorption patterns and excitation peaks.
Colored Diamonds are very rare and extremely expensive.With HPHT Process these diamonds are affordable and can be bought by many people.

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