Man is the most evolved being of this planet. What sets a human apart
from other living beings is that he has the most advanced mental capabilities.
This has provided man with the ability to discern, comprehend and most
importantly it triggers inquisitiveness. Curiosity is what has led to many
important inventions and discoveries in the history of mankind. Man has
observed the way nature works and tried to imitate the same. One of the finest
example of this is synthetic diamonds, where in scientists have tried to
reproduce the same extreme conditions in a laboratory, which exist in the core
of the earth for diamond formation.
Synthetic diamonds are also known
as “cultured/lab-grown” diamonds. They can be defined as man-made
diamonds which ape a natural diamonds physical, chemical, thermal and
electrical properties and essentially have the same chemical composition.
In the early 1950’s the General Electrical scientists were trying to
create synthetic diamonds with High Pressure High Temperature(HPHT) methodology.
Diamond and graphite are both forms of carbon but, the stronger bond of the
carbon atoms in diamond is what gives it its prized form. The biggest challenge
that stood in front of scientists was how to convert graphite into diamond.
Experiments were carried out for years wherein graphite was subjected to
intense heat and pressure but it was all in vain. Until they discovered that in
a meteorite crater in Arizona, diamonds were found in a substance called
troilite. This is what gave them a break through. In the year 1956, they had succeeded in their experiment where they put together troilite and graphite and
then exposed them to immense pressure and temperature.
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| HPHT DIAMOND PRESS |
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| HPHT DIAMOND SYNTHESIS |
Major advancements have come about in this technology of
manufacturing synthetic diamonds. Mainly now synthesis takes place with the
help of a diamond seed crystal. Graphite
along with catalyzers are placed in huge diamond presses. The chemical reaction
which take place under high heat and pressure result in crystallisation of
diamond. This technique is now most importantly used for enhancing the color of
natural diamonds. Usually diamonds are divided into two categories – Type 1 and
Type 2 depending on the kind of impurity they have and these are subdivided
into two categories each.
Type 1 diamonds are abundant in nature and mostly contain nitrogen.
These diamonds are usually colorless, yellow or brownish. Whereas, Type 2
diamonds are rare and contain little or no nitrogen or boron.
TYPE
|
IMPURITY
|
COMMON COLORS
|
Type 1 A
|
Nitrogen – plentiful
|
Colorless, yellow
|
Type 1 B
|
Nitrogen – less
|
More yellow
|
Type 2 A
|
Nitrogen – little/no nitrogen
|
Colorless, brown or grey
|
Type 2 B
|
Nitrogen – little /no nitrogen/ boron
|
Blue
|
The HPHT treatment is mostly carried out on Type 2A diamonds to
convert them from brown to colorless
diamonds. Type 1A diamonds are treated to produce green, yellow and orange
colors.
Another method which was synthesising diamonds in the early 1950’s was
Chemical Vapour Deposition commonly known as CVD. This process uses thin
diamond chips as a seed on which the diamond crystals grow. Crystallisation
takes place when methane and hydrogen are subjected to low pressure and heat in
a vaccum chamber. Heat and pressure break down hydrogen molecules into single
atoms (atomic hydrogen). This hydrogen reacts with methane. This reaction
results in formation of pure carbon which starts attaching itself to the seed
crystal and as more and more carbon atoms attach themselves the diamond crystals
grow.
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| DIAMOND SEED CRYSTALS |
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| CVD GROWN DIAMONDS |
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| CVD VACCUM CHAMBER |
Earlier the use of synthesised
diamonds was limited to industrial purposes wherein diamond cutting tools and
various other equipments were made. But now, the application of synthetic
diamonds is not only limited to gems and jewelry industry. Due to its excellent thermal, electrical,
physical and optical properties it has stretched its wing over various other
sectors such as health care and electronics industry.
Certain companies are producing excellent quality synthetic diamonds.
Among the top producers are Gemesis, Chatham and Scio Diamond Technology
Corporation which are American
companies. AOTC – Advanced Optical Technologies Corporation from Netherlands.
Synthetic diamonds have revolutionised the market and they are
affordable and within the reach of masses. Along with it consumers who are
concerned about blood diamonds, it also gives them an opportunity to wear
responsibly created diamonds. Synthetic diamond is an excellent invention of
the ever inquisitive human being, except for the challenge that it has posed in
front of the natural diamond industry.
*The Author is a Colored Stone Graduate from Gemological Institute of America, Mumbai and a Diamond Graduate from Solitaire Diamond Institute, Bangalore. She also holds a Diploma in Jewelry Designing & Manufacturing from Jewelry Product Development Centre, Jaipur. She also blogs at 'The Jewel Affair'.
*Picture Courtesy: Google Images
