CBI vs ACA - Another pic and vid comparison

[Lula]

No vendor sticks to an exact cookie cutter proportions when it comes to diamonds. However, they try to optimize the light performance as mentioned earlier.

I'm just sharing a copy/paste of the proportions I've noted from the CBI inventory while I was trying to search out my stones. As you can see, the pavillion angle varies from 40.7-40.9 and the visual differences from .1 change in the pavillion is huge.

CBI
56.8, 61.2, 34.2, 40.7, 55 77 - OP's
56.7, 61.3, 34.5, 40.9, 51 43.3, 77, tm
57.2, 60.9, 34.1, 40.8. 51 43.1, 78, tst
56.1, 61.9, 34.4, 40.8, 51 43.1, 77, tst
56.9, 61.4, 34.6, 40.8, 50 43.1, 77, tm
56.4, 61.5, 34.3, 40.8, 51 43.1, 77, tst
56.4, 61.7, 34.5, 40.8, 50 43.2, 76, tm

ACA
55.5, 61.2, 34.2, 40.7, 50 43, 76, tm
56, 61.4, 34.4, 40.8, 51 43.1, 77, tm
56.7, 61.3, 34.6, 40.8, 51 43.2, 76, tm
55.9, 61.9, 34.7, 40.8, 53 43.1, 76, tst
56, 61.7, 34.7, 40.7, 53 43, 76, tm
56.6, 61.6, 34.6, 40.7, 53 42.9, 78, tm
56.5, 61.5, 34.4, 40.7, 51 43, 77, tm

BlueMA, you and the others who focus obsessively on the numbers and on the "cheat sheet" that is shared with every new poster are missing the point. What I'm saying, and what I believe the other CBI owners on this thread are saying, is that the numbers tell only part of the story. The numbers help narrow the field, so newbies can be reasonably sure that they are getting a well-performing diamond. But the numbers in and of themselves do not tell you about the diamond's cut precision. Cut precision makes a big difference in consistency in appearance and performance across stones from the same brand. I do not believe any of us on this thread are claiming that CBIs are "better" than other brands. What we are saying is that CBIs have a consistent appearance and performance across stones, which we find appealing. Threads from 2010 and earlier that address cut precision, cut consistency, optical symmetry, yaw, painting and digging, etc., helped me extend my understanding of diamond appearance and performance beyond a simple comparison of table, crown, and pavilion angles. In this way, I agree more with David (Rockdiamond) from DBL than I do with the posters who focus solely on the numbers. Shocking, I know!

 

[blueMA]

I do not believe any of us on this thread are claiming that CBIs are "better" than other brands.

Good agreed!

 

[egemnoel]

No vendor sticks to an exact cookie cutter proportions when it comes to diamonds. However, they try to optimize the light performance as mentioned earlier.

I'm just sharing a copy/paste of the proportions I've noted from the CBI inventory while I was trying to search out my stones. As you can see, the pavillion angle varies from 40.7-40.9 and the visual differences from .1 change in the pavillion is huge.

CBI
56.8, 61.2, 34.2, 40.7, 55 77 - OP's
56.7, 61.3, 34.5, 40.9, 51 43.3, 77, tm
57.2, 60.9, 34.1, 40.8. 51 43.1, 78, tst
56.1, 61.9, 34.4, 40.8, 51 43.1, 77, tst
56.9, 61.4, 34.6, 40.8, 50 43.1, 77, tm
56.4, 61.5, 34.3, 40.8, 51 43.1, 77, tst
56.4, 61.7, 34.5, 40.8, 50 43.2, 76, tm

ACA
55.5, 61.2, 34.2, 40.7, 50 43, 76, tm
56, 61.4, 34.4, 40.8, 51 43.1, 77, tm
56.7, 61.3, 34.6, 40.8, 51 43.2, 76, tm
55.9, 61.9, 34.7, 40.8, 53 43.1, 76, tst
56, 61.7, 34.7, 40.7, 53 43, 76, tm
56.6, 61.6, 34.6, 40.7, 53 42.9, 78, tm
56.5, 61.5, 34.4, 40.7, 51 43, 77, tm

I might not have been clear before. You can solve brightness neatly with external averages. But most of the numbers you posted stand for 8 separate measurements. Some of them stand for 16 and it actually would not matter if you knew all 57 measurements for each line, since it is only external facet data. You would have to un-average the averages, organise by facet groups, correlate XYZ lighting with each unique pairing and quartet and octet (and beyond) and work to recreate that specific diamond’s 3D virtual facet pattern that ultimately dictates the fine nuances of fire, scintillation and contrast.

I imagine you know there are people who believe any EX or Ideal diamond will be just as good as the next and the next. I absolutely do not believe that it is the case from my personal observations. I don’t know if you do. But I gather you believe a line of averages reveals everything about a diamond’s specific character. I totally disagree, but I respect your right to have that opinion. This is a place for dialogue, not censorship. I make my own testimonials, based on what I observe. So do you and if you were to come have a pint in Ireland and observe diamonds with me and you still felt differently that’s fine too. If we all felt the same way it would be a boring world!

 

[blueMA]

I imagine you know there are people who believe any EX or Ideal diamond will be just as good as the next and the next. I absolutely do not believe that it is the case from my personal observations.

Actually, this is absolutely the case. At a certain point, human eyes can't distinguish between one superideal diamond to another well cut similarly proportioned ideals, just as in clarity IF vs VS. I've absolutely seen this myself time and over IRL along with many others here on PS, and in fact most trade experts agree on this regard. In addition, peoples preferences for brightness/fire vary greatly, so what you personally prefer doesn't mean that's what others would want. I understand some want the "mind" assurance.

Just recently, I'm sure you've read this post?
https://www.pricescope.com/communit...between-wf-and-cbi.239329/page-3#post-4315090

I rest my case, since I see we're going in circles here.

 

[autumngems]

I'm too confused now, I have been searching for a stone and worried about HCA scores now I need to worry about skinny or fat arrows, ugghhhh

 

[Dancing Fire]

I'm too confused now, I have been searching for a stone and worried about HCA scores now I need to worry about skinny or fat arrows, ugghhhh

Look for stones with 76-77 LGF.

 

[Yang Kin]

I'm too confused now, I have been searching for a stone and worried about HCA scores now I need to worry about skinny or fat arrows, ugghhhh

Don't worry too much about HCA if you have the actual performance images, which are much more useful.