Shallow? Depth and crown angle different from usual ones

[Ashleigh]

Hi,

I came across these stats on a stone.

Table 55.2%
Depth 60.9%
Crown angle 33.8
Pavilion angle 40.8

When I saw the depth and crown angle, I was really to give it a miss. But since it's from a reputable vendor, I doubt they'll sell duds. So I ran the HCA and it turned out to be 0.9 though it's out of the square box.

What does it mean? Pls help in my understanding. Thanks

 

[yssie]

Numbers are fine - incl. depth and crown, what do you feel is the issue?

GIA rounds crown to the nearest 0.5.. which gives you some idea that performance is pretty tolerant of crown angle variations from any given "ideal" compared to say pavilion angle, which GIA rounds up to the nearest 0.2deg. And even there the academic differences we can discuss 'til the cows come home often have perhaps surprisingly little bearing on what a non-professional consumer might actually appreciate IRL.

ETA: AGS proportions charts here: http://agslab.com/trade_research_and_development_proportion_based_cut_grade.php (ID grade on the Diamond Quality Document (Platinum report) contingent on results from 3D ray tracing simulation as well as listed proportions)

 

[kdn2684]

Numbers are just numbers and they are used to determined which diamond has a better chance of being a good one vs a bad one. Great numbers don't mean that the diamond performs. From doing my short research, i'd pay more attention to the ASET and Idealscope (with help from the experts) images as that will tell you how well your diamond performs. i bought the following diamond from Whiteflash's Virtual Selection with a lower crown angle then you that still had a good ASET and Idealscope image.

[URL='https://www.pricescope.com/community/threads/help-reviewing-aset-and-idealscop-of-a-round-diamond.160306/#post-2913264#p2913264']https://www.pricescope.com/community/threads/help-reviewing-aset-and-idealscop-of-a-round-diamond.160306/#post-2913264#p2913264[/URL]

 

[Ashleigh]

Yssie, kdn, thanks for the replies.