Do you know the growth process of HPHT diamonds in the laboratory?

What are HPHT diamonds?

HPHT stands for High Pressure and High Temperature, which is a main method used to grow diamonds in the laboratory. This diamond growth process requires carbon to be placed in a temperature and pressure environment that simulates the heat and pressure conditions when natural diamonds are formed deep in the earth.

HPHT diamonds are diamonds that are artificially generated and manufactured to simulate the crystallization characteristics of natural diamonds. They are real diamonds in every sense of the word, and their chemical, physical, atomic, optical and all properties are the same as natural diamonds.

Similarly, HPHT diamonds also have certificates issued by international authoritative diamond appraisal institutions. And like natural diamonds, they follow the international 4C standards and supply the entire diamond industry chain together with natural diamonds.

What is the growth process of HPHT diamonds?

1. The diamond seeds are placed under specially created pressure conditions.

2. The growth chamber is heated to 1300-1600 °C and the pressure is higher than 870,000 pounds per square inch (about 5,998,440 Pa).

3. The molten metal decomposes the high-purity carbon source.

4. Carbon atoms are deposited on a small diamond seed crystal, and the synthetic diamond begins to grow.

5. The lab-grown crystal is then cut by a diamond cutter.

In detail, HPHT diamonds are grown in a small chamber that is located inside a device that can generate very high pressure. The carbon raw material (such as graphite) in the chamber is dissolved in a metal flux composed of elements such as iron (Fe), nickel (Ni), and cobalt (Co), thereby reducing the temperature and pressure required for diamond growth. The carbon material then moves to the cooler diamond seed with the help of the flux and crystallizes on it to form a synthetic diamond crystal. The crystallization process takes days to weeks to form one or more crystals.

Natural diamond crystals tend to be octahedral, while HPHT synthetic diamond crystals usually have cubic surfaces in addition to octahedral surfaces. Due to the different shapes of natural diamond crystals and HPHT synthetic diamond crystals, their internal growth patterns are also very different. The difference in internal growth patterns is a reliable way to distinguish natural diamond crystals from synthetic diamond crystals.

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