How Are Diamonds Grown?
Replicating what happens deep beneath the earth is difficult, time-consuming, and expensive, but the end result is identical to what has been mined for centuries. There are easier ways to do it, but only the process that we use, replicates Mother Nature to rearrange atoms to grow a beautiful diamond as unique as a fingerprint. We do this because we care about the planet and want the jewelry and diamonds that we sell to bring the same sense of caring and growth into the personal relationships that they symbolize.
HPHT
High Pressure High Temperature method replicates the natural process of diamond formation under the Earth’s crust like a giant pressure cooker.
It starts from the following: we stack a diamond seed, graphite & metals (growth catalysts) inside the small cubic cell and then we place that cell into a hydraulic press. Under enormous pressure (5-6 GPa) and scorching temperature (~1500 ℃) graphite and metals start to melt to eventually form a diamond around the seed. The whole process takes about 2-3 weeks from start to finish.
Grows in 14 different directions. Size is limited by the size of the cubic cell and applied technology (usually from 1ct up to 15 ct of polished). Growing methods also influence types of inclusions and possible color of the stone. For example, HPHT stones may include metals due to the applied technology. CVD stones usually may have dislocations which leads to greyish or milkish tint.
Possible colors are from D to I, usually Colorless or Near Colorless groups.
Possible clarity from IF to I1, usually VS clarity group.
All shapes are available, though Pears/Ovals/Marquise are rare due to low yield.
CVD
Chemical Vapor Deposition can be described as growing diamonds from carbon-containing gas. (Reactor picture)
CVD process starts from the following: we put a diamond plate inside the vacuum chamber and heat this plate up to 800 ⁰C. Then the chamber is filled with carbon-rich gas (usually methane) which is also heated up to 3000 ⁰C with a microwave beam. It is done in order to break molecular bonds and release carbon atoms which are then deposited onto the diamond plate. Slowly but surely the diamond grows upwards (it's length and width are limited by the size of the plate). CVD requires 1-4 weeks from start to finish (depending on required weight).
Features: Grows in one direction - upwards, therefore limited by the size of initial diamond plate and applied technology, usually no more than 5ct polished. CVD stones are Type II a, unless they are colored.
CVD stones are usually Near Colorless, but rarely better or lower. They also might have greyish or brownish tints.
In terms of clarity CVD stones lay between IF to SI, mostly VS.
All shapes are available though Pears/Ovals/Marquise are rare due to low yield.