Princess Cut Diamonds: I understand
that the princess shape does not have the same grading
parameters as the round brilliant for the quality of cut. How
can I tell just from the GIA certificate if a princess shape
is a well cut stone with good brilliance & fire?
-- Izumi I., Tokyo, Japan
This is a good
question and it deserves a comprehensive answer, so... here goes!
AGS has just recently
received a grant to develop standards and a grading scale for
fancy shape diamonds. However, as you mentioned, there is not
a set of guidelines in place at the moment. Therefore, assessment
of cut grade is left up to individual suppliers and retailers.
Also, we believe strongly
that a set of guidelines is only good when they are properly
explained. We do NOT believe that there is such a thing as an
Ideal Cut diamond, because the question must be asked: ideal
for whom? The guidelines should be defined for each different
set of tastes, and accxording to the nature of the internal structure
of the material. Diamond from one mine can look entirely different
than one from a different mine, even when both are cut to exactly
the same proportions.
When you and I look
at the same diamond, one of us might love it while the other
does not. The difference is in personal taste. Take rounds, for
instance. If I like a lot of fire and you are more focused on
overall brilliance, the proportions will need to be different
to achieve the two different effects in a stone.
Let me give an example.
If I like lots of fire, I will want a round diamond with the
smallest table of about 53% or so, with a crown angle of around
34.5%. On the other hand, a person that likes brilliance over
everything else would probably prefer a larger table of about
60% and total depth becomes very important.
So the same applies
to a Princess Cut and any other fancy shape. The range of possibilities
for a Princess Cut in the industry is much wider than for rounds.
We have seen stones with a table of 75% and depth of 75% and
it still looks very nice. But measurements and other details
are not easy to fix for fancies. Best just to see them, or ask
dealer how it
looks and be sure to get an excellent return policy and satisfaction
Also, for now, the most
important factors in your search might be polish and symmetry.
Look for excellent or at least a very good grade for these two
areas on the cert. Depth and table percentages could be a little
larger than for rounds, around 5-10% larger we might estimate.
Without published guidelines
for fancy cuts, we would prefer not to give any exact guidelines
at this point, since they would only be our own opinion, and
might not agree with yours or with any other experts.
On the other hand, when
we do hear about definitive, well-accepted guidelines for fancies
from a reputable source, we will post them here for all to know.
Keywords: princess shape,
princess cut, good cut, cut grade, cut guidelines, table, depth
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