re: can I deduce the actual cut quality for a pear based on details?

[Marjan12]

HI all -

I''m finding so many sites that describe pear cuts differently - some say ideal, some say no ideal but excellent, some say no ideal or excellent for a pear but very good... I''m wondering, can I tell myself what the cut is, based on the measurements provided, like table & depth, girdle, etc?

One stone I am looking, that is labeled a "very good" cut, has:
a table of 55%
depth of 60.3%
a girdle of "thin,"
and a very good polish & symmetry. Don''t these details tell me what the cut quality is, regardless of lable they give it?

Another stone, that is labeled an "excellent" cut, has:
a table of 57%
a depth of 63.8%
a girdle of medium to very thick
and very good polish & symmetry.

Isn''t the first stone a better cut than the second one?

 

[stone-cold11]

Cut is more about light return. Symm and polish are just that, symm and polish of the facets.

No lab grades pear in light return, so these description of cut is from the vendor, might be good or bad description, depending on the vendor. No way to tell anything except general outline of the cut. The best way is to view it yourself or for the vendor to provide an ASET image.

 

[Gypsy]

Light performance and actual pics of the diamond. Or picking the diamond in person is the best for pears. You just can't do by the numbers. I mean, you could get lucky doing it that way. But you need to either see the stone, or if on the net have pics of the stone and an IS (and an ASET if you can get one).

The labels mean nothing. I'm sorry.

 

[Gypsy]

Here are a bunch of "ideal" labeled pears with similar specs click on the pics and compare their looks:

http://www.jamesallen.com/diamonds/D-VS1-Ideal-Cut-Pear-Diamond-1195364.asp Nice numbers, but what looks like a large bowtie

http://www.jamesallen.com/diamonds/I-VS2-Ideal-Cut-Pear-Diamond-1210738.asp Giant bowtie


http://www.jamesallen.com/diamonds/E-VS2-Ideal-Cut-Pear-Diamond-1217706.asp Looks promising. I'd get an Ideal Scope on it. **

http://www.jamesallen.com/diamonds/G-VS2-Ideal-Cut-Pear-Diamond-1239673.asp So similar to the one above by the numbers, but hello bow tie.


http://www.jamesallen.com/diamonds/G-VS2-Ideal-Cut-Pear-Diamond-1220703.asp Can't tell if the pic is bad or if the stone has some serious dark zones

http://www.jamesallen.com/diamonds/D-VS2-Ideal-Cut-Pear-Diamond-1239175.asp Nicest numbers, but ... is it APPRECIABLY better than the one with the ** above from the pic? Nope. In fact I like the ** one better from the pics.

http://www.jamesallen.com/diamonds/G-VS2-Ideal-Cut-Pear-Diamond-1241873.asp Hello bowtie. It's a very symmetrical bowtie though.

 

[Lorelei]

Date: 6/28/2009 7:58:46 PM
Author:Marjan12
HI all -

I''m finding so many sites that describe pear cuts differently - some say ideal, some say no ideal but excellent, some say no ideal or excellent for a pear but very good... I''m wondering, can I tell myself what the cut is, based on the measurements provided, like table & depth, girdle, etc?

One stone I am looking, that is labeled a ''very good'' cut, has:
a table of 55%
depth of 60.3%
a girdle of ''thin,''
and a very good polish & symmetry. Don''t these details tell me what the cut quality is, regardless of lable they give it?

Another stone, that is labeled an ''excellent'' cut, has:
a table of 57%
a depth of 63.8%
a girdle of medium to very thick
and very good polish & symmetry.

Isn''t the first stone a better cut than the second one?

Oh good - another pear thread, I love this shape and am very interested in them!


The term Ideal Cut can be used rather loosely in some cases, is no guarantee of a well cut pear. Images are really needed especially detailed photos and an ASET image if buying online. If you are not familiar with ASET, this page explains.

http://www.highperformancediamonds.com/index.php?page=education-performance

Either of the pears above could be worth further investigation, although the numbers only give a chalk outline of the stone, with the exception of the very thick girdle on the second, both could be potentially nice pears. If you investigate the second, make sure the very thick part of the girdle isn''t an issue by getting the vendor or trusted expert to check. If this takes up much of the girdle it can waste weight/ face up size. So really no, you can''t get a good idea of cut quality based on a few measurements and no way to tell without images which is the best cut.

Pears can vary tremendously in shape and this can come down to personal taste, also many pears show an effect called a bow tie. This is a dark area which runs across the middle of the stone which quite literally looks like a bow tie. This can be minimized in some cases but sometimes not altogether so you might want to examine each diamond carefully for this if you can view them in person ( tilt them and check out away from the store lights) or ask the vendor to inspect them if shopping online.

 

[oldminer]

You can use an ASET to make subjective grading of light return, but ASET gives you little idea of the proper cut of the diamond. A diamond can be wrongly shaped or not durable enough even with a great ASET image, but it is a starting point if you have the diamond and an ASET image. However, I''d suggest a better way to screen pear shapes is the AGA Cut Class system which can be found on pricescope and also on www.gemappraisers.com in an automated grader. Just put in the shape and a few parameters and you will arrive at a very safe way to know the diamond has wonderful potential. If a Pear scores 2B or better, it will probably be pretty nice looking and if it happens to score 1B or better it will almost certainly have no problems AND great looks. Only if a diamond has intenral problems or if the cutter was unskilled (doubtful) would a reasonably well cut pear shape have some truly bad appearance or severe durability issue. You will find many fancy shapes too deeply cut and while they may be very attractive, they look small for the weight you are paying for because their visual size is taken up by depth rather than lenght and width.

 

[Rockdiamond]

Hi Marjan12,
Short answer- no.

It''s no simple matter as there are sellers trying to use labels to indicate they have an"ideal" or well cut stone.
The labeling of cut by sellers ( such as calling a pear shape "excellent") is IMO out of line as there are no accepted standards for what makes a pear shape "excelent" in terms of cut.
If a stone has a GIA "EX cut grade- or AGS0, a seller may say they are selling an "Ideal" cut, or an "Excellent" cut.
But neither lab grades Pear Shapes for cut.

IN terms of charts, I respectfully disagree with David Atlas.
There are indeed stones that will fall under the right depth table crown angles etc that won''t appeal to everyone. This is especially true with pear shapes where a stone might have "perfect" table and depth, but not have a shape you find pleasing.

Conversely there are amazing stones that may have a table or depth that the cart indicates is somehow sub-par that may be the most appealing stone you see.

 

[oldminer]

Rockdiamond, you have taken the logic backwards. I have said you can't judge a diamond by the numbers, but you will find few diamonds within the parameters provided which fail to be of great potential for at least consideration. I would think you would realize that a smart cutter, and most cutters are very smart about diamond cutting, would not purposely make an ugly diamond within the rather narrow constraints of the parameters provided unless they had a great piece of rough which would lend itself to a finer make to begin with. Cutters don't make ugly out of potentially fine material. I'm sure you would avoid a parametrically fine make which had poor visual appeal. Everyone would.

Because rough is costly, because the market is so smart and competitive, I believe that these parameters have exceedingly few exceptions. There are diamonds outside these parameters worthy of a look, too, but if they are far from these parameters, there is likely to be some substantial compromise taking place. These are SCREENING tools, not ultimate selection tools.

See the thread I began about parametric screening just a short time ago.

 

[Rockdiamond]

Date: 6/29/2009 8:04:45 AM
Author: oldminer
You can use an ASET to make subjective grading of light return, but ASET gives you little idea of the proper cut of the diamond. A diamond can be wrongly shaped or not durable enough even with a great ASET image, but it is a starting point if you have the diamond and an ASET image. However, I''d suggest a better way to screen pear shapes is the AGA Cut Class system which can be found on pricescope and also on www.gemappraisers.com in an automated grader. Just put in the shape and a few parameters and you will arrive at a very safe way to know the diamond has wonderful potential. If a Pear scores 2B or better, it will probably be pretty nice looking and if it happens to score 1B or better it will almost certainly have no problems AND great looks. Only if a diamond has intenral problems or if the cutter was unskilled (doubtful) would a reasonably well cut pear shape have some truly bad appearance or severe durability issue. You will find many fancy shapes too deeply cut and while they may be very attractive, they look small for the weight you are paying for because their visual size is taken up by depth rather than lenght and width.

HI David,
As my signature contains my name, please call me David!
In bold ( it''s your bold, not mine) is the statement which I feel is inaccurate.
The shape of a pear shape is crucial. No matter what the table depth, or light return.
You used the term "bad appearance" which makes it sound as though there would be no reason a person would not like a diamond falling in those ranges unless there was "internal problems or the cutter was unskilled"
Given the wide range of models ( the outline shape) for a pear, it''s not possible to say that there won''t be shoppers who would not like a stone based solely on it''s shape ( regardless of it''s numbers)- this is common with a pear shape.

Conversely, I''ve found that many diamonds that fall outside the prescribed ranges ( some far outside) are extremely attractive- based on shape, brilliance and a number of factors.

 

[LD]

Date: 6/28/2009 8:36:44 PM
Author: Gypsy

Here are a bunch of ''ideal'' labeled pears with similar specs click on the pics and compare their looks:

http://www.jamesallen.com/diamonds/D-VS1-Ideal-Cut-Pear-Diamond-1195364.asp Nice numbers, but what looks like a large bowtie

http://www.jamesallen.com/diamonds/I-VS2-Ideal-Cut-Pear-Diamond-1210738.asp Giant bowtie


http://www.jamesallen.com/diamonds/E-VS2-Ideal-Cut-Pear-Diamond-1217706.asp Looks promising. I''d get an Ideal Scope on it. **


http://www.jamesallen.com/diamonds/G-VS2-Ideal-Cut-Pear-Diamond-1239673.asp So similar to the one above by the numbers, but hello bow tie.


http://www.jamesallen.com/diamonds/G-VS2-Ideal-Cut-Pear-Diamond-1220703.asp Can''t tell if the pic is bad or if the stone has some serious dark zones

http://www.jamesallen.com/diamonds/D-VS2-Ideal-Cut-Pear-Diamond-1239175.asp Nicest numbers, but ... is it APPRECIABLY better than the one with the ** above from the pic? Nope. In fact I like the ** one better from the pics.

http://www.jamesallen.com/diamonds/G-VS2-Ideal-Cut-Pear-Diamond-1241873.asp Hello bowtie. It''s a very symmetrical bowtie though.

This is a fantastic example of why you need to buy a pear shape with your eyes and not by numbers!