Do you think that if all the money that has been spent on
diamond exploration were spent on say alexandrite exploration there
would be many more alexandrites on the market? Would small
alexandrites be as common as small diamonds? How about any other
gemstone that we now consider rare?
If the same amount of money spent on mining diamonds were spent on
practically any gemstone, I suppose there would be many more of
them. But since diamonds are so widely marketed and alexandrite is
not, it wouldn’t be economically feasible to spend that kind of
money on alexandrite mining. I don’t believe that the conditions for
the formation of alexandrite was ever as favorable as it was for
diamonds, so I doubt that they would be as common. Diamonds have
been found in every part of the world except Antarctica, whereas
alexandrite has not. As far as other gemstones we consider to be
rare concerning this discussion, I don’t think so, either.
Alexandrites, demantoid Garnet, Paraiba tourmaline - these and many
other rare gemstones lack something diamonds offer: durability. I’ll
agree that there are tougher stones than diamond, but none of them
can wear longer.
Has anyone ever seen the actual pile of rough or cut diamonds
supposedly stored by DeBeers?
I haven’t personally seen it, but all diamond rough is well
documented. It’s just too big a business to fudge about it. Most of
De Beers’ mining processes are mechanized, so it would be difficult
for them to pretend otherwise.
At what point in diamond size and quality does a stone qualify
as rare?
To me, any ‘extra fine’ gemstone qualifies as rare. The geologic
conditions under which gemstones form are incredibly uncommon. There
may be billions of carats of diamonds in the earth’s mantle, but
until there is a kimberlite (or lamproite) eruption to bring them to
the surface, there they will stay.
Kimberlites are actually fairly widespread. In the 1990s, there were
around 6,000 of them known around the world. The thing is, fewer
than 1,000 of them contained any diamonds. If there are no diamonds
in the kimberlite’s path to the surface, there are no diamonds in
the pipe. Of the 1,000 that contained diamonds, only perhaps 50 of
them were diamondiferous enough to be economically mined, and only
20 or so remain today. Now, here’s what actually qualifies just
about any diamond (indeed, any gemstone) as rare - The first
diamond-bearing kimberlite eruption occurred around 2.5 billion
years ago by scientific estimate. The newest emplacement happened
around 20 million years ago. No one has ever seen one. There may be
undiscovered, diamond-laden pipes still to be discovered, but in the
end, supplies are limited. It is absolutely within the realm of
possibility that we may eventually mine every diamond on the planet
before any more reach the crust of the earth through a kimberlite
eruption. And there’s no guarantee that the next eruption will
contain diamonds. In fact, the statistics are against it, 120:1.
While looking around the average diamond district, they don’t seem
rare - they seem to be everywhere. But the reality is that most are
included, colored or in some other way (cut, etc) common (meaning
less rare). The better the clarity and color, the larger the size,
the more rare. And even supplies of inferior goods won’t last
forever. It may be another 20 million years (or longer) before any
more diamonds are rushed to the surface. Personally, I’m not so sure
the human race will be around that long.
Does anyone know what percentage of diamonds that are mined
are cuttable into jewelry grade diamonds?
It depends on the mine, itself. Primary deposits such as kimberlite
pipes have the lowest percentage of cuttable material. Or, at least
makable material. Other sources, such as alluvial and marine
deposits have a typically lower overall yield in carat weight, but
the rough has been tumbled to the point that either the finest
pieces with the fewest flaws remain intact, or they make it to the
deposit already broken or cleaved into smaller pieces. In that case,
the work of planning, cleaving and sawing is minimalized to the
point that a much larger percentage of the rough is cuttable. In
1960, more than 80 percent (by weight) of diamonds were recovered
from alluvial deposits. By the early 1990s, it accounted for only 25
percent, so percentages fluctuate over the years. In marine mining
in particular, gem quality stones are extremely high by percentage.
For example, in Namibia, any fractured stones that survived the trip
were broken apart during the trip. As a result, around 90 to 95
percent of the diamonds mined there are gem quality.
According to one GIA publication, the world’s estimated diamond
production in 1999 breaks down like so:
15 percent gem-quality rough
39 percent near-gem rough
46 percent industrial rough.
The actual amount of finished goods is somewhat hazy from there. As
technology increases, more and more near-gem and industrial rough
can be acceptably enhanced or somehow justified as jewelry material.
Also, these percentages are for rough. In the gem-quality category,
finished goods will wind up closer to 12 percent, due to losses in
cutting.
What is a jewelry grade diamond?
Not so long ago, that was a supremely difficult question to answer -
it would have been an absolutely subjective matter. But with today’s
technologies, the answer is: They all are. In the past, there was a
lot of brown and black ‘bort’ that would have gone on to become
industrial grade abrasive. Now, black bort is used as high end
jewelry. Brown diamonds have been given names like ‘champagne’ and
‘cognac.’ Many are now irradiated and/or HPHT enhanced to fancy
colors like blue and green. With the advent of lasers,
difficult-to-cut rough such as carbonado (a typically black,
somewhat aggregate form of diamond that can’t be polished by
lapidaries) may now be fashioned in certain ways. Macles are also
easier to work with due to lasers.
By traditional view, some of the above doesn’t qualify as ‘jewelry
grade’ diamond, but there are many high end designers who are using
non-traditional bort to excellent effect. Does the designer who
intersperses black diamonds in a pleasing pattern among colorless
diamonds in platinum regard it as jewelry grade? Probably only the
ones who consider themselves ‘ottists.’
James in SoFl
