Shallow crown angle and height

[KobiD]

Noob mistake above. My comments re AGS000 should have only read AGS0. MIstakenly thought 000 indicated Light performance, proportion, and finish.

In the end even a bad AGS0 is going to out perform the stone we saw in person. I'm sure the shallow cut would have too.

 

[TitanCi]

That's absolutely fair. But do remember it's not a single measurement - they all work together. With a table in the 55-58 range a 40.8-41.0 average PA combined with a 32.5-33.0 CA can be extremely bright. Whenever you're looking at shallow crowns a smaller table % will help build crown height and help dispersion. I'd urge you to stay with lower halves in the high 70s... And do post candidates here. The community tends to give strong feedback.

I can attest to this! I bought my wife's first stone with a CA of 33. Its numbers allowed it to score 0.9 or whatever on the HCA and have an amazing IS. That stone performed like no other. Great stone. All the angles, numbers fall in the ranges John posted here, but that's at the limit of shallow that I would ever go for again. Awesome stone

 

[yssie]

Noob mistake above. My comments re AGS000 should have only read AGS0. MIstakenly thought 000 indicated Light performance, proportion, and finish.

You aren't wrong. AGS000 originally meant cut, colour, and clarity grades of 0, but that isn't really the case any more.

John Pollard posted about this several years ago:
[URL='https://www.pricescope.com/community/threads/ags000-or-triple-zero-definition.24289/']https://www.pricescope.com/community/threads/ags000-or-triple-zero-definition.24289/[/URL]

 

[KobiD]

Thanks Yssie

 

[dpichugin]

I've found a scientific article of gemology which covers the subject of this topic:

https://pdfs.semanticscholar.org/c834/c8e476bdf7386b8698848304d3fdcc9e3a3b.pdf

Also, I have a question about the diamond geometry below. It is E color and XXX by GIA.
Bottom of it looks good to me, top is shallower than I wish.
It has 1.0 HSA score. with excellent fire, brilliance, though very good light return.
Also HSA report says it will appear dark if viewed closeup.
My concern is that "it will appear dark if viewed closeup" what do you think?
Also, star length is 45% -- what effect that may have? usual numbers are 50%-55%
Thank you