What
are
'Antwerp', 'Premium'
or 'Ideal' cut diamonds
Firstly
you must understand that we do not, here in Europe,
in the trade, use the terms 'premium' or
'ideal',
we use the term 'very good' in order to identify them.
The
term 'good' would be used as ' average' cut
and the term 'unusual' in order to identify a 'poorly'
cut diamond.
Now within the term 'very good' there
are various types of cut diamonds all cut to within
certain fixed parameters. The whole idea is that these parameters all
'work' with one another,
in reality
they 'work' in different ways.
You can have a 'very good' cut diamond, within the 'very good' parameters which
will look different to another, of identical weight which has also been cut
to within these fixed parameters.
You will now understand that the differences are subtle, only a professional,
using his trained eye will be able, using the appropriate magnification and lighting
conditions, to tell the differences.
Having said that there are also very noticeable differences as well within
this 'very good' parameter range.
Some diamonds which are cut to within 'very good' proportions are cut 'to weight'. Cutting
to weight is a term used by professionals to identify a diamond
cut in order to lose the minimum amount of rough material.
This presents the diamond with a small table, around 56% to
57%, a thickish girdle, around 4% to
4.5% and a high crown height, around 15% to 16%.
These diamonds will all have very good light refractive qualities but this
is not, to our mind, what is most important.
What is important is the actual 'look' of the diamond on the finger.
This 'look' must bring together both very good sparkle and very good actual
visual size to weight ratio. Indeed some of these 'cut
to weight' diamonds
look much smaller, at equal weight, than other not 'cut to weight' ones.
These very well 'cut to weight' diamonds
have, through the decades, found their way to
the US market, reasons being that they were cheaper to produce and the US customer knew
no better and was talked into believing that this was the best,
but who are we to argue with this as we produce 'cut to weight' diamonds which
are sold to our US clients.
In Europe, we and our clients, know that it is not, our
European clients look for what is called, in the trade,
as the 'Antwerp' cut, the Americans have labeled their 'built up', 'cut
to weight' stone, the 'ideal'
cut or 'Premium' cut in some instances.
Both these cut to fixed proportions stones have very good
sparkle, but to the eye, there are appreciative differences.
I have been talking about 'very good'(premium)
cut diamonds, which I must add, as the differences
in cut are very subtle, will not influence the price very much.
However, with the 'average' or 'good' cut to fixed proportioned diamonds, these parameters have
been extended in order to add possibilities.
The diamonds cut to within these parameters will not sparkle as much, will
lose their sparkle more quickly and when produced
will cost, therefore, less as they would have lost
less rough
diamond weight during the cutting process.
Actual visual size may not be affected as both 'thickish' and 'spread' stones can
suffer from these extended parameters.
They are or rather should be discounted to the consumer who should be made aware of
what he/she is actually purchasing.
The diamond report (certificate) will not mention
these 'nuances' within the 'very good' range of parameters
but should mention whether the proportions are 'good', 'very
good' or
'unusual'.
In fact the GIA certificate will not
show either the crown height or the pavilion depth, just
showing the total depth, which, is a useless parameter.
This is, to say the least, quite misleading to the
client.
The rest is left to the expert professional whose expertise should be sufficient in
order to
advise. Unfortunately jewellers do not have this level of diamond expertise as
they do not specialise in diamonds alone, we do, we are 'real' diamond experts,
we grade literally hundreds of diamonds per day, a
jeweller, however important, may grade or
rather look at a couple or half a dozen at most, they rely, therefore, mostly on
their supplier and simply pass on the
description or grade this supplier has given to them to
their customers.
Always happy to
answer any further questions on this subject.
George
Zaidmann
Certified Gemmologist
Expert diamond appraiser
Member of the Antwerp Diamond Bourse since 1972
For more information
please click on the link below
http://www.professionaljeweler.com/archives/news/2004/020704story.html
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