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Ideal Cut Vs Proportions related to sparkle & brilliance?

footshooter5

Rough_Rock
Joined
May 2, 2011
Messages
30
Hello all!

This is my first foray into the Pricescope forums (though I've been lurking here for a little while :)). I've been doing as much research and as much homework as time permits, but I have yet to find a very solid answer to this question...

I'm curious as to which of the two factors is most important in determining the sparkle, brilliance, and fire of a stone...is it the cut, or the proportions of the diamond, or perhaps a combination of the two? I'm looking to purchase a stone between 1.23. and 1.3 cts, with an F or G color, and VS1-SI1 clarity, and have a budget of about 11,000 dollars.

I think to my soon to be fiance ;-) the most important thing is cut, so I would like to find something that's "Ideal" or Ex/Ex, and GIA or AGS, but I just came across an article highlighting the importance of having a well proportioned diamond. ALL of the stores that I've been visiting keep pushing cut cut cut as the only determining factor regarding scintillation, sparkle, etc... but now I'm not so sure.

If any of you can shed light onto this for me, I would greatly appreciate it, being a diamond newb ;-)

Thanks in advance!
 

Stone-cold11

Super_Ideal_Rock
Joined
Sep 9, 2008
Messages
14,069
Re: Ideal Cut Vs Proportions related to sparkle & brilliance

Cut is proportion.
 

slg47

Ideal_Rock
Joined
Apr 4, 2010
Messages
9,667
Re: Ideal Cut Vs Proportions related to sparkle & brilliance

Stone-cold11|1304345793|2909956 said:
Cut is proportion.
yep, means the same thing :)
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,378
Re: Ideal Cut Vs Proportions related to sparkle & brilliance

Proportions and Cut are frequently used in a synonymous way. However, the resultant beauty and life of a diamond comes from its optic properties which are highly altered by cloudiness, visible inclusions, and dark hues of body color. Other than surface reflection, no life comes from within a black diamond. It does not matter if such a stone is cut to ideal proportions or not although some sellers tout superb cutting on black diamonds for no reason I can fathom.

The Cut of a diamond may also be only used to denote its shape, such as "pear" or "round". Sellers who look to prey on impulsive buyers often cover "Cut" with the shape outline and say nothing more. Sometimes they may say they only sell the finest cuts and never show you any evidence to prove it.

Proportions always refer to measured elements of the stone and their relationship to one another. Don't single out one or one group of proportions as a goal in a diamond purchase. It is much more complex and requires the entire group of measured proportions to work well with one another to create a top grade cut. Even then, looking with your eye and various screening tools will be useful, too.
 

Todd Gray

Brilliant_Rock
Trade
Joined
Jan 20, 2009
Messages
1,297
Re: Ideal Cut Vs Proportions related to sparkle & brilliance

The subject of "Cut" can be a little confusing because the term "Cut" is used to describe different things by various members of the jewelry trade... Many retail jewelers use the word "Cut" to describe "Shape" such as "Marquise Cut" or "Round Brilliant Cut" and so on, as David Atlas pointed out.

However in the inner sanctum of diamond buying for the diamond industry (trade) the term "Cut" is used to refer to the Diamond Cut Quality in terms of proportions, polish, symmetry and visual performance. And there are some of us who take it a little further and break the concept of "Cut" into different segments referred to as "Cut Precision" and "Cut Performance" as defined below.

The term Cut Performance refers to the Cut Quality of the diamond in terms of the overall combination of proportions, meaning the measurements of the primary sections of the diamond and the consistency of facet shape, size and alignment within each section.

The term Cut Precision is used to indicate the degree of Optical Symmetry to which the diamond was crafted. Quite simply, it is how precisely the diamond cutter aligned the facets of the diamond opposite of each other; this is judged using tools such as a Hearts & Arrows viewer; ASET Scope; Ideal Scope; etc.

Focus on Cut Performance first, this will be the proportions, polish and symmetry of the diamond; these factors are disclosed on AGS and GIA diamond grading reports from June 1, 2005 forward... Then focus on Cut Precision which is hinted at on newer AGS Performance level lab reports which include an image of the ASET Scope impression of the diamond and further explored by obtaining ASET / Ideal Scope / Hearts & Arrows / images from each vendor - many of the vendors here on PS make these images readily available on the diamond details pages for each diamond.
 

denverappraiser

Ideal_Rock
Trade
Joined
Jul 21, 2004
Messages
8,747
Re: Ideal Cut Vs Proportions related to sparkle & brilliance

Proportions is the physical measurements of the stone both in direct terms and in relation to one another.
'Ideal' is a grade assigned by AGSL and a few others to describe a particular set of attributes for a stone. Note that GIA does NOT have an 'ideal' grade.

For some labs, the grade 'ideal' is strictly a matter of proportions but In both the GIA and AGS cut grading approaches, polish and symmetry are consided as well before assigning a finish grade. In both of these cases, there are also measurements included in the decision that don't otherwise appear on the report.
 
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