H & A/ Ideal cut?

jmartini · Mar 2, 2006

Thanks so much to everyone for your help with my dark looking ring. We are going back in this Saturday to look at some more stones...I have a few questions I hope you can answer for me.

1. Since we want to look at more stones, the owner asked me what proportions I was looking for in my RB diamond. He claimed that my diamond was an Ideal cut, but even the Depth (63.2%) seems deeper than any Ideal proportions I have seen even with all the variants. So, is the Tolkowsky''s cut the best example for me to give him? Personally, I don''t think I should have to give him any proportions. I expect him to show me the best looking diamonds for my money (which is what we said before).

2. Can a diamond still look fabulous (sparkle, scintillation, etc) and *not* be a H & A diamond? I know there is a H & A loupe, but can you also see it with the naked eye or with a regular 10x loupe? Also, I''m assuming that just because it is a H & A diamond, it does not mean that it will be be the best looking diamond, right?

3. What is HCA?

4. The owner claims that my diamond was "machine cut" vs. "hand cut", thereby making it an Ideal Cut with all of the proper proportions. He did not have any of the crown or pavillion angles info for me on any of the diamonds (Shouldn''t he be able to get those for me?) Is there such a thing as just "machine cut"? This is supposed to be a very reputable store.

Lastly, if I stay with Good or above in Polish and Symmetry, is that good enough? The owner says that as long as it is good or better it will not affect the sparkle or brilliance or beauty of a diamond at all (at least not to the naked eye)

I''m so sorry for the long post. Thank you for all of your help! BTW, for those of you that use the Ideal-Scope, do you just walk in to the jewelers and sit down and use it on the diamonds? Since my ring was custom, we can''t get our money back but we can exchnage, so we are *stuck* using this jeweler

...we ordered the scope yesterday.

Thanks again

,
Jen

belle · Mar 2, 2006

Date: 3/2/2006 9:15:39 AM
Author:jmartini

1. Since we want to look at more stones, the owner asked me what proportions I was looking for in my RB diamond. He claimed that my diamond was an Ideal cut, but even the Depth (63.2%) seems deeper than any Ideal proportions I have seen even with all the variants. So, is the Tolkowsky's cut the best example for me to give him? Personally, I don't think I should have to give him any proportions. I expect him to show me the best looking diamonds for my money (which is what we said before).

the easiest way to go about getting a well cut stone (ideal) would be to get one with a new ags report that grades light performance.

the table/crown/pavilion angle relationship is important. some combinations will work together better than others (the hca will confirm which) but in general, you can look for tables in the 54-57 range..crown angles in the 34.5-35 range..pavilion angles in the 40.6-41 range.

Date: 3/2/2006 9:15:39 AM
Author:jmartini

2. Can a diamond still look fabulous (sparkle, scintillation, etc) and *not* be a H & A diamond? I know there is a H & A loupe, but can you also see it with the naked eye or with a regular 10x loupe? Also, I'm assuming that just because it is a H & A diamond, it does not mean that it will be be the best looking diamond, right?

yes it can, as long as it has great angle relationships. the instrument you use to see the h&a pattern is called an h&a viewer. it is different from a loupe and will have a colored piece of film inside that reflects the facet pattern so it is easy to see. the best looking diamonds have angles that work together to reflect light within the diamond and back to your eye efficiently. optical symmetry (such as in the h&a stones) have been proven to make a difference in performance.

Date: 3/2/2006 9:15:39 AM
Author:jmartini

3. What is HCA?

holloway cut adviser. it is used to determine which proportions and angle relationships will work to best handle light within a diamond and back to your eye. basically, it is used to find which stones have the potential to perform well (and which might be dogs!

)

Date: 3/2/2006 9:15:39 AM
Author:jmartini

4. The owner claims that my diamond was 'machine cut' vs. 'hand cut', thereby making it an Ideal Cut with all of the proper proportions. He did not have any of the crown or pavillion angles info for me on any of the diamonds (Shouldn't he be able to get those for me?) Is there such a thing as just 'machine cut'? This is supposed to be a very reputable store.

now if it that were true, why are there so many different ideal cuts? (that aren't always so ideal?

)
his statement is ridiculous.
if he does not have a sarin machine (or similar) to measure the diamonds, then no, he would not be able to get that information for you. the only way you could get it (other than sending the stones to someone who can measure) is to find some with the new grading reports from either ags or gia. they both list this information.

Date: 3/2/2006 9:15:39 AM
Author:jmartini

Lastly, if I stay with Good or above in Polish and Symmetry, is that good enough? The owner says that as long as it is good or better it will not affect the sparkle or brilliance or beauty of a diamond at all (at least not to the naked eye)

you would be fine with good or above polish/symmetry they alone do not directly effect the 'sparkle' but keep in mind that well cut stones are going to have these little details attended to. if a cutter took the time to get everything else right, the polish/symmetry should be up there too.

best of luck jen!

JohnQuixote · Mar 2, 2006

Hey Jen.

As you learned, there are different interpretations of Ideal. If you trust this jeweler and the diamond is amazing to your eyes that’s what is most important. Some of us are very puritanical about cut and pedigree - but you should get caught up in that only as much as you want to.

With that said, here are comments: 1. Tolkowsky is a set of proportions that is reliably beautiful. The common interp of ‘Ideal’ (AGS) is based on measurements near Tolkowsky’s, but other beautiful configurations are possible. Your jeweler’s interpretation of Ideal may be a different or wider range. This would not be surprising, since diamonds cut within the strict AGS Ideal range are less common than those cut outside of it.

Edited to add: I just saw Belle’s suggestions. They are good, actually more strict than traditional AGS Ideal parameters. I suggest depth between 59.5 and 62% as a great range to assure proper spread for weight, but others accept different ranges. Belle's advice to seek a new AGS report with the light performance grade is very sound, but they are not widely used by common jewelers.

2. A diamond can look fabulous and not be a H&A diamond. Many diamonds cut within a strict range by their nature show some degree of precise patterns due to the care taken when cutting.

3. The Holloway Cut Adviser. It predicts how a diamond may perform based on 5 very important parameters. It's intended for rejection, not ultimate selection. Here.

4. Some diamonds are cut using machines, particularly mass-manufactured ones and very small diamonds. Machines have come a long way but cannot judge the ‘touch’ to finish a premium diamond like a human being can. The most premium makes are still brillianteered by hand.

5. If you are seeking Ideal parameters (strict ones) the best diamonds typically come with Ideal/Excellent/VG symmetry and polish. It’s a by-product of the extra care usually taken by the cutter. In technical terms there is not a lot of visible difference between VG/EX/Ideal. Naked eye experts could sometimes pick out G symmetry, but most often the differences are those of craftsmanship, not perceptual beauty.