Help with HCA Tool for 1ct,VS2,G diamond

[J-Man]

I'm fairly new to this forum and was looking at this diamond on b2cjewels:

http://www.b2cjewels.com//dd-2476536-1.00-carat-Round-diamond-G-color-VS2-clarity.aspx

The HCA tool says it's rated 1.3....however the cut rating is only Very Good. Are there other factors to consider as to why this diamond cut isn't rated Excellent?

Thanks

J

 

[darkadam]

Looks good to me, below are the numbers. Interested to know why it isn't excellent as well...
Could it be possibly due to optical symmetry ? (don't think gia grades that...)

Depth
Depth 61.8 %
Table 55 %
Crown Angle 34.5°
Crown Height 15.5%
Pavilion Angle 40.8°
Pavilion Depth 43.0%
Star Length 55%
Lower Half 75%
Girdle Slightly Thick, Faceted, 3.0%

 

[diamond-enthusiast]

Penalized for brilliance and contrast patterns. Basically, it didn't make it visually for an excellent cut.

 

[yssie]

Penalized for brilliance and contrast patterns. Basically, it didn't make it visually for an excellent cut.

Wow. Really?

1. How on earth could you guess that from just those numbers without seeing the stone?
2. This is a pointless response - there's absolutely nothing that helps further OP's understanding of what's going on. A helpful response would include an explanation, or at the very least an elaboration on exactly what you mean by "brilliance" and "contrast patterns" and a link or two to threads or documentation with more info...
3. Had you actually looked at the report you would have noted this comment: "Cut grade affected by brillianteering".


OP, that comment is the reason for the GIA downgrade. 'Brillianteering' ('painting' and 'digging') translates into girdle treatments that GIA considers to be in excess of what's necessary to actually cut the stone. There's a lot more info here:
GOG tutorial: http://www.goodoldgold.com/4Cs/NewCutGrading/PaintingandDigging/
Lots of pics: http://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds
Old but good intro thread: [URL='https://www.pricescope.com/community/threads/girdle-treatments-cheated-girdles-tweaked-girdles-digging-painting.36102/']https://www.pricescope.com/community/threads/girdle-treatments-cheated-girdles-tweaked-girdles-digging-painting.36102/[/URL]

GIA has sorta a zero-tolerance policy but EightStar specializes in precision-cut stones w/ significant crown painting - that's what yields that bright red IS with no leakage at the girdle:


(http://www.proposalring.com/buyingEightStar.htm)

Without more info we can't say anything about exactly what treatments this stone has had, or degrees of treatment, so we can't say anything about what it actually looks like and whether or not you'd likely see a difference IRL. Can your vendor get you some photos or a scan?


ETA: Don't use HCA as a selection tool - it's designed to be a blunt weeding tool and it's not fine enough for any other purpose.