Ask A Scientist General Science Archive

name         David W.
status       other
age          30s

Question -   I recently saw a show on gemstone quality synthetic
diamond manufacturers and what companies like DeBeers are doing to detect
them.  Basically, the research at DeBeers currently focuses on detection
of nitrogen trapped in the diamond matrix with spectroscopy.  Since the
atmosphere is mostly nitrogen all diamonds contain some as they are
formed.  Natural diamonds have had "millions" of years to leach off any
trapped nitrogen and contain almost none.  DeBeers concludes that their
system of counterfeit detection is nearly foolproof and "obviously"
synthetic diamond manufacturers do not have millions of years to wait for
their product to mature.

My question is:
Why couldn't a company that has already spent millions for hydraulic
presses spend a few thousand more to eliminate the nitrogen?  If they
precipitated the graphite out of a nitrogen free solution and then
processed the stones in a vacuum chamber they could completely eliminate
all nitrogen from their stones.  This seems to be the obvious next step--I
assume if it would work someone would have already done it, so why would
it not work?
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Eventually I think the market will make the call...if you remember "cultured
pearls"  were not at first accepted, but their beauty made the final
decision...as will the diamonds.

Peter Faletra Ph.D.
Assistant Director
Science Education
Office of Science
Department of Energy
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Hi,

As you know, diamond making process is rather difficult and complicated: 
simulating what it took nature millions of years to accomplish in under 
100 hours. But the work is continuing and I expect that we will have real 
(synthetic) diamond of any desired quality and color in not too distant 
future.  Size is quite another problem.

But in response to your question, there are ways to produce diamonds 
without the yellow color. The yellow color is due to ATOMIC nitrogen 
dispersed in the diamond.  Mined diamond (note that I do not use the term 
natural diamond) often has nitrogen but the atoms of nitrogen have 
coalesced rendering the diamond colorless.

That fact points the way to an approach to make the yellow color go away: 
by forcing nitrogen atoms to combine. This has been partially successful: 
by heating diamond over a long time, the yellow color has been reduced. 
But this is a lengthy and as-yet incomplete process.

The other technique that has been used successfully is to use a
"getter" (a material that attracts nitrogen) when making diamond. Aluminum 
is one such material and by using it colorless diamonds have been produced 
in Russia.

A third option, as you correctly noted, is to grow diamond in a 
nitrogen-starved environment.  It does not have to be  vacuum, however.
I do not know the practical difficulties with this approach but given the 
high pressure high temperature environment one operates in, it may be 
presently uneconomical.  I think when assembly-line type production 
facilities come about, the issue will be properly addressed.

One final point about diamonds in general.  Diamond as a high-priced 
luxury item is one of the largest marketing gimmick  created by man.
Behind all this is a very powerful cartel, unregulated and 
supernational.  It controls the market by controlling the mines, supplies, 
and distribution channels. That there are no major or potential 
alternative suppliers or  competitors speaks for itself.  I do not know of 
any other commodity (and yes, despite advertisements to the contrary, 
diamond is a commodity) controlled by one single company worldwide.   The 
problem it faces now is how to maintain its monopoly by convincing the 
unsuspecting public that diamond is not diamond unless it is mined. The 
situation is perhaps similar to the days where hybrid /engineered plant 
seeds were considered fake, unnatural, synthetic.

There is no doubt that REAL diamond (ones with perfect and specific 
crystal structure, specific impurity, color, etc.) will be the ones grown 
by man in factories in the next few years.   All the proposed detection 
techniques to determine if the origin of a diamond is a mine or a factory 
misleads the public.  Indeed, if what is great about diamond is its beauty 
(and from a consumers' point of view it is), why would one care about its 
source?  The attempt presently is to perpetuate the false notion that 
diamond from ore has an investment aspect to it.
It does not because if the market were open and free competition would 
take off, prices would collapse, and diamond for the most part would be 
treated like other stones. It is an irony that the artificially high price 
of diamond has fueled the research that will shortly undermine the price 
structure.  Diamond will perhaps be the tulip of the 21st century.

Ali Khounsary, PhD
Argonne National Laboratory
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There are a number (more than 10 at least) ways to "date" minerals using
radioactive decays of minor constituents, or the ratio of various nuclides.
This is a very sophisticated science and technology. I am not a gemologist,
nor an expert in the dating of minerals, so like you, I am making some
reasonable guesses and assumptions.

1. I am not sure that companies that make "synthetic diamonds" are targeting
the gem market as a place where their high temperature/pressure technology
would fit. I would think that they would be attracted to the industrial 
diamond
market where diamonds are used as grinding media etc. This is much less
demanding of quality and size diamonds than the gem market.

2. Yes, if they were going head-to-head with the gem diamond business, they
could be able to purge the system of N2 or even put the entire machine in a
vacuum. But their attempt a forgery would be much more complicated. They
would have to start with fairly "old" graphite because any "new" graphite
would result in diamonds that have much more carbon 14 activity than the
"geological" grade.

3. Given the lucrative nature of diamond market for companies like DeBeers,
I would be very surprised if they do not have a whole battery of chemical and
physical tests for diamond "signatures". I would be very surprised that they
would not be able to tell,  not only what country, or part of the world, a
diamond originated, but even be able to tell you which mine it came from,
and when it was mined. I would be surprised if they did not have a paper trail
accounting for every diamond of significant value -- where it went to from
the mine, who bought it, how many and what kind of diamonds were cut, where
these diamond "daughters" then went, and so on.

These cartels want to preserve their monopoly, and they have very deep
pockets stuffed with lots of cash that a make synthetic diamond makers seem
like paupers. Somewhere in this world DeBeers probably has their own
synthetic diamond producing facility and know as much as anyone what the
pluses and minuses are.

This is high stakes business and the "haves" are not going to let the "have
nots" into it just because of a few trillion dollars.

Vince Calder
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