Very Good 2ct vs. Ideal/Hearts and Arrows 1.5 ct.

[melz]

Here are the stats:

2 ct, F, SI2 (eye clean), Very Good cut GIA cert.

Table % 54
Depth% 62.4
Crown angle %: 34
Pavilion angle %: 40.6

No culet
Girdle: medium to slightly thick
Flourescence: None
Polish: Excellent
Symmetry: Very good
HCA score = 0.8

This is up against (and the same price as) a G color AGS ideal cut hearts and arrows 1.5 ct. SI, also eye clean. HCA = 1.

In a perfect world I could view them side by side in person but that''s not going to happen. I''m just wondering if, except for size, I would be able to tell the difference if they were side by side. Any thoughts are appreciated!

 

[elle_chris]

This is a toughie. You''d probably be able to see a performance difference is certain types of light assuming the second is really an ideal cut h&a. Can''t you have both sent to an appraiser and check them out in person?

There''s really no way to tell if you''re willing to sacrifice size for cut unless you see them both.

I''m probably keep looking and go for an excellent GIA cut with great proportions in an H color, 2ct range.

 

[John P]

Date: 2/25/2009 4:40:49 PM
Author:melanie987123
Here are the stats:

2 ct, F, SI2 (eye clean), Very Good cut GIA cert.

Table % 54
Depth% 62.4
Crown angle %: 34
Pavilion angle %: 40.6

No culet
Girdle: medium to slightly thick
Flourescence: None
Polish: Excellent
Symmetry: Very good
HCA score = 0.8

Do you know why VG? 54/34.0/40.6 can earn EX if the minor facets are in practical ranges, and VG finish is still permitted in EX. Was there a comment about brillianteering?

 

[elle_chris]

John, I''ve been under the impression that a crown angle of 34, should have a pavilion angle that''s 40.8-41. How wrong am I?

 

[stone-cold11]

Date: 2/25/2009 5:02:16 PM
Author: John Pollard
Do you know why VG? 54/34.0/40.6 can earn EX if the minor facets are in practical ranges, and VG finish is still permitted in EX. Was there a comment about brillianteering?

John, I tried facetware and apparently GIA drop the cut grade because of the depth, 62.3% being the cut off.

 

[stone-cold11]

If same price, I would give the 2ct a shot.

 

[phildominator]

Surprised nobody has asked you to provide ASET or IS photos...That''s pretty much standard operating procedure here.

You could have GIA Ex/Ex/Ex and a <2 HCA score, yet still have a diamond with poor performance with light leakage.

 

[John P]

Date: 2/25/2009 5:09:25 PM
Author: elle_chris

John, I've been under the impression that a crown angle of 34, should have a pavilion angle that's 40.8-41. How wrong am I?

It's really about all the proportions together elle... With that said, I have some guidelines which I've seen repeated here and there. Lady Lorelei has quoted a "Cliff's Notes" I penned some years ago that I consider a good dot-to-dot in terms of finding the overlapping 'bullseyes' between systems such as AGS, GIA, HCA and AGA.

Those CNotes for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded) are as follows: A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle is 40.6 lean toward a 34.5-35.0 crown. If pavilion angle is 41.0 lean toward a 34.0-34.5 crown.

Again, no one (or two) numbers can dictate decisively what one of these complex firecrackers will look like, but those are some guidelines... I'm even more a fan of those common requests for IS and ASET photos above and beyond numbers analysis.

 

[John P]

Date: 2/25/2009 6:20:57 PM
Author: Stone-cold11

Date: 2/25/2009 5:02:16 PM
Author: John Pollard
Do you know why VG? 54/34.0/40.6 can earn EX if the minor facets are in practical ranges, and VG finish is still permitted in EX. Was there a comment about brillianteering?

John, I tried facetware and apparently GIA drop the cut grade because of the depth, 62.3% being the cut off.

You're right SC. Those numbers with 62.3% get EX. With 62.4% it's VG. Normally up to 62.9%D is allowed but the lab guys have told me there are girdle thickness / depth functions that kick in with some of these combos. Interesting.

Considering that is a 0.1% depth discrepancy I'd say this is a very borderline VG (depending on minors). Could be bargain-priced.

 

[elmo]

Date: 2/25/2009 10:03:17 PM
Author: John Pollard
Considering that is a 0.1% depth discrepancy I'd say this is a very borderline VG (depending on minors). Could be bargain-priced.

How big can the culet be and still get EX cut?

Time for a shave?

That is unless it's 2.00ct.

 

[Lorelei]

Date: 2/25/2009 10:00:31 PM
Author: John Pollard

Date: 2/25/2009 5:09:25 PM
Author: elle_chris

John, I''ve been under the impression that a crown angle of 34, should have a pavilion angle that''s 40.8-41. How wrong am I?

It''s really about all the proportions together elle... With that said, I have some guidelines which I''ve seen repeated here and there. Lady Lorelei has quoted a ''Cliff''s Notes'' I penned some years ago that I consider a good dot-to-dot in terms of finding the overlapping ''bullseyes'' between systems such as AGS, GIA, HCA and AGA.

Those CNotes for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded) are as follows: A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle is 40.6 lean toward a 34.5-35.0 crown. If pavilion angle is 41.0 lean toward a 34.0-34.5 crown.

Again, no one (or two) numbers can dictate decisively what one of these complex firecrackers will look like, but those are some guidelines... I''m even more a fan of those common requests for IS and ASET photos above and beyond numbers analysis.

Those are very useful Sir and are of frequent help to many!

 

[John P]

Date: 2/25/2009 10:33:25 PM
Author: elmo

Date: 2/25/2009 10:03:17 PM
Author: John Pollard
Considering that is a 0.1% depth discrepancy I'd say this is a very borderline VG (depending on minors). Could be bargain-priced.

How big can the culet be and still get EX cut?

Time for a shave?

That is unless it's 2.00ct.

VSM and SM still get EX. At about 0.3% (VSM) depth would be reduced to 62.3. You might not even lose a point.

Clever Elmo. Be careful or DeBeers will send the silent black helos to abduct you - though with the economy it may be silent black Vespas or something now.

 

[melz]

Wow this is a ton of useful information thank you. I apologize for not replying to questions within this link, I actually thought my original question did not post and stumbled across it just now.

I don''t have any pictures of the 2ct, idealscope or otherwise, and they won''t let me send it to an appraiser unless I buy it. I would love for that to be an option. Although it can be returned, I''m hesitant to put multiple diamonds on my credit card. There was not a comment about brillianteering.

Okay, now I''m going to pour over alll those numbers everyone provided and see what I come up with. May just have to bite the bullet and order it ...

Thanks again!

 

[Kelli]

This choice is a toughie. I''m a stickler for cut since finding PS, but with such a great HCA score, I don''t know that I''d let the "true hears and arrows" thing affect my decision. That is a significant size jump! If you can''t get idealscope images or send it to an appraiser, I''d probably get the 2.0 with full intent to return it if it didn''t prove worthy. OR... I''d lower the color a bit and see if you can find a 2 ct. H/I ideal H&A as someone esle already said. I probably wouldn''t spend the money on an F, but that''s just me.

 

[melz]

You are absolutely right! I was watching a goodoldgold tutorial and realized I definitely can't tell between an F and a G, and maybe not between a G and an H. When viewing an Asscher in person I could, but that's probably due to the shape (these stones are rounds).

Anyway this 2ct is a blue nile stone priced around 13,500. Might just bite the bullet and buy it. Such a nice conundrum to have.

 

[Sizzle]

Date: 2/26/2009 2:15:21 PM
Author: melanie987123
You are absolutely right! I was watching a goodoldgold tutorial and realized I definitely can''t tell between an F and a G, and maybe not between a G and an H. When viewing an Asscher in person I could, but that''s probably due to the shape (these stones are rounds).

Anyway this 2ct is a blue nile stone priced around 13,500. Might just bite the bullet and buy it. Such a nice conundrum to have.

Is this diamond eyeclean? I can''t see why it would be so cheap!

 

[glitterata]

Totally the 2 ct. If you don''t like it when you see it, you can return it. But that''s a huge jump in size for what might well be an invisible difference in cut. Even if the 2 ct does turn out to be slightly less well cut than the 1.5 ct, you still might prefer the significantly bigger size. It certainly doesn''t sound badly cut.

 

[melz]

I was told it is eye clean. Per my separate post, I will not be getting the BN 2ct. If you are interested, you can find it here:

http://www.bluenile.com/round-diamond-2-carat-very-good-cut-f-color-si2-clarity_LD01487969