People have been making diamonds in laboratories for more
than fifty years.  The basic patents have long since run
out, and the price of diamonds remains high.

Three reasons.  First, even the most recent, still-patented
techniques, cannot practically duplicate top-end natural
gem-quality diamons.  The one-carat blue-white "flawless",
which is essentially the benchmark of the industry, is
still somthing you have to hunt for in a mine.  Or you
can have one made in a laboratory as a stunt, but you
can't have them mass-produced for sale with any technology
we know of.

Second, people don't *want* synthetic diamond gemstones.
The ones who might have wanted such a thing, have long
since moved on to cubic zirconia or whatever; the ones
who are still buying mediocre half-carat diamonds of the
sort that can be mass-produced in a factory, want them
not for what they intrinsically are but for what they
represent - the closest thing people on a budget can
get to the archetypal one-carat blue-white flawless.
Which is to say, among other things, natural and mined.

Third, the techniques for producing synthetic diamond,
are not themselves cheap.  Well, industrial abrasive
diamond, yes, sort of, but not any sort of synthetic gem
diamond.  Some of them are pure laboratory curiosities
of no practical or economic significance; others can be
industrialized, but you're not going to be seeing the
output at your local 99-cent store any time soon.

Not really, no.  DeBeers has long since lost its monopoly
in the field; the Australians and Canadians and Russians
provide most of the world's gem diamonds now and each will
gladly fill any supply shortfall the others might try to
create.

The profitability of both natural and synthetic diamonds
is for the most part maximized by increasing demand, by
means of some rather noteworthy and successful advertising
campaigns.  

You might still be able to arrange cheap diamonds, but by
definition nobody will care.

Mmmmmmmmmmmmmm

Well equipment can tell them apart!

What is interesting is that deBeers gave Jewelers in Australia free
special equipment to tell them apart because most Jewelers could not
tell them apart!

That is for sure. The Russians are apparently sitting on a fortune of
diamonds and not selling them for that reason.

I kind of doubt it.  A lot of people who want diamonds for jewelry want
them because they're expensive, not because they're just diamonds.  All
De Beers has to do is keep pumping the idea that their diamonds are what
the consumers want and artificial diamonds are fake, regardless of
whether they're indistinguishable.  De Beers already has methods of
tracking the authenticity of their diamonds, so whether you can't tell
them apart is really irrelevant in that respect.

Diamonds for industrial purposes is another thing, but there already De
Beers doesn't have a lock on that market.

I know one company bought some Russian technology, and was near being
able to commercially make inexpensive yellow diamonds.

Another company was a bit further off with chemical vapor deposition.
Did De Beers buy their technology?

Also, sapphire seems like a very good lens material, because it has not
only a high index, but low dispersion. Diamond has a high dispersion -
and isn't it birefringent too?

In any case, according to the latest issue of Scientific American, a
very thin coating of silver on a lens can produce, at least at a short
range, the ability for that lens, through a partial adoption of
characteristics of negative refraction, to focus light to make details
shorter than its wavelength.

Just the thing to keep Moore's Law going for a few more years!

Of course, there may still be uses for a diamond lens. A flint element
to go with a sapphire lens as the crown?

John Savard
http://www.quadibloc.com/index.html

Marc VB a écrit :

fu2 sauvage.

Hervé <YFAB>