9mm 11mm GHI Color CVD HPHT Raw Uncut Diamond 8.0ct To 8.99ct

Square Shape 9mm - 11mm GHI Color Cvd Hpht Uncut Rough For Making Round Brilliant White Color Jewelry

CVD Lab Grown Diamonds Description

Laboratory-grown diamonds, also known as laboratory-made diamonds, man-made diamonds and synthetic diamonds, are pure carbon diamonds that simulate the natural growth process of the earth under strictly controlled laboratory conditions.

What is high pressure high temperature (HPHT) diamond?
HPHT stands for High Pressure High Temperature Method, which is a main method used in laboratories to make diamonds. This diamond growth process requires carbon to be exposed to extreme temperature and pressure conditions, which simulate the extreme heat and pressure conditions when natural diamonds are formed in the depths of the earth.

The diamond seed crystal is placed under specially designed pressure conditions, and the growth chamber is heated to 1300-1600 °C, and the pressure is higher than 870,000 pounds per square inch (approximately 5,998,440 Pa). The molten metal decomposes high-purity carbon sources and deposits carbon atoms in one place. After the synthetic diamond starts to grow on a small diamond seed crystal, this laboratory-made crystal is cut by a diamond cutter.
In detail, HPHT diamonds are grown in a small chamber, which is located in a device that can generate extremely high pressure. The carbon raw materials (such as graphite) in the cabin are melted in a metal co-solvent composed of iron (Fe), nickel (Ni), cobalt (Co), etc., thereby reducing the temperature and pressure required for diamond growth. Then, the carbon material moves to the lower temperature diamond seed crystal with the help of the co-solvent, and crystallizes on it to form a synthetic diamond crystal. The crystallization process takes several days to several weeks to form one or more crystals.

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

Synthetic gemstones that have been faceted usually show special color distribution characteristics, fluorescence partitions and twinning patterns, which are all related to the cross-shaped growth zone structure of the crystal. Sometimes this type of gemstone will also have dark metallic flux inclusions. In some cases, this material will exhibit phosphorescence, that is, after being exposed to an ultraviolet light source, it can continue to emit light even if the light source is turned off.

The production of colorless HPHT synthetic diamonds was once a big problem. Nitrogen turns diamonds yellow, so it must be excluded from the growing environment. In addition, high-clarity colorless diamonds require a longer growth time, and the temperature and pressure conditions required for their growth also need better control.

Parameters of CVD Lab Grown Diamonds

CVD Lab Grown Diamonds​ Introduction

​Natural diamonds are created by nature and are the result of high temperature and pressure formed over billions of years. The Rough Lab Grown Diamonds are produced in the laboratory, usually in a few weeks. The chemical difference between the two is same.

So how do you distinguish between Rough Lab Grown Diamonds and natural diamonds?

There is no obvious difference between the Rough Lab Grown Diamonds and natural diamonds. Even professional gemologists need special equipment to identify them. By zooming in, professionals will be able to discern subtle contrasts in diamond inclusions grown and mined in the laboratory.

CVD Lab Grown Diamonds Details