Growing - Man Made Diamonds
MiaDonna’s® Man Made Synthetic Diamonds are created using one of two different
growing techniques that both result in a pure carbon diamond when complete.
- High Pressure High Temperature or HPHT is our main growing process.
- Chemical Vapor Deposition or CVD is used more commonly for producing
diamonds for industrial purposes, but is also used to produce Man Made Diamonds
for finished jewelry.
1. High Pressure High Temperature Lab Grown Synthetic Diamonds
High Pressure High Temperature or HPHT is the main diamond growing method to grow real, high-quality diamonds. HPHT recreates a diamond's natural growing environment found deep within the earth. The machines used have the ability to build up pressure of almost 60,000 atmospheres and temperature of 2,500°C.
How HPHT grows a diamond
The growth cell itself contains all the elements needed to grow a diamond,
including a tiny diamond seed, highly refined graphite and a catalyst consisting
of a mixture of metals and powders. The growth cell is placed in the center of
the HPHT machine. Very consistent temperatures reaching 1,300 degrees Celsius
and over 50,000 atmospheres of pressure are applied to the growth cell. The
catalysts inside the growth cell are the first to react to the added heat and
pressure by changing from solid to molten form.
The catalyst molten solution now causes the graphite (carbon) also in the
growth cell to dissolve. Once all the required conditions within the growth cell
have been met the cooling process begins. This highly controlled cooling process
takes place over many days and allows the carbon atoms to build up on top of the
diamond seed that was part of the original growth cell mixture. The growth cell
is removed from the HPHT machine once the growth cycle is complete. The new
rough diamond is cleaned and now ready for final cutting and polishing.
The entire HPHT growing process requires an incredibly controlled environment
to produce a gem quality diamond. Any shift or change during growth can cause
the diamond itself to stop growing or can cause any additional growth to be
heavily included and become unusable. Every grown diamond must go through an
entire growth cycle before the machine can be opened. It is only after the HPHT
machine is opened that we are able to see the finished diamond along with the
color, clarity and size that was produced.
Within the HPHT process there are 3 different types of machines/techniques
used for producing Synthetic Diamonds. These are:
1. Bars Press
Currently the Bars Press is the most effective tool used for producing gem
quality diamonds. The Bars Press uses a combination of inner and outer anvils to
apply hydraulic pressure to the growth cell within the unit.
2. Belt Press
The Belt Press is the founding technology behind growing diamonds. A Belt
Press can be very large, even as tall as a small home and can produce many
diamonds in only one cycle by using two huge anvils that press together to
create the necessary pressure. The Belt Press is capable of producing gem
quality diamonds but is most commonly used to produce diamonds for industrial
purposes as well as diamond in powder form.
3. Cubic Press
A Cubic Press is used to create diamond powder for industrial purposes. Cubic
presses can also be very large and use 6 separate anvils that press onto a small
cube to create the necessary pressure for crystal diamond growth.
2. Chemical Vapor Deposition Lab Grown Synthetic Diamonds
Chemical Vapor Deposition or CVD environments use a small percentage of one
atmosphere of pressure. Carbon based gases like methane are heated until the
gases inside the environment break apart and allow the carbon atoms within the
gas to separate. These tiny carbon atoms fall onto a diamond substrate and, over
a few days, build up layers resulting in a rough diamond crystal. The majority
of diamonds produced from CVD are best used for semiconductors, but there are
also many gem quality CVD diamonds entering the market.