Confused re: GIA/AGS Proportions vs. HCA

[MissElizabeth]

Okay, so I'll show my ignorance here!

I got the proportions on my new studs and somehow they fit in the GIA/AGS proportion tables around the Excellent range (provided I'm reading them right), but which score absolutely horrendously on the HCA (>4). What gives? In all the old threads I can find it's usually a "steep/deep" issue, which may be the case with stone #2 - but is it with both?

Thanks in advance all!

Stone 1:
0.50 carat (5.09x5.14x3.10)
I color, SI2 clarity
Depth 60.6%, Table 60%, Pavilion Angle 41.35, Crown Angle 34.5, Med Girdle, Good Polish, Very Good Symmetry

Stone 2:
0.52 carat (5.12x5.14x3.20)
H color, SI1 clarity
Depth 62.4%, Table 60%, Pavilion Angle 41.35, Crown Angle 34.5, Medium Girdle, Good Polish, Very Good Symmetry

Edited to add: They show up beautifully in person so I'm keeping them, but just have to solve this bewilderment that's in my head around why the HCA is so low...

 

[whitewave]

Frankly, I wouldn't keep them. You can find better stones.

I kept a HCA 2.5 and I think it is wonderful. But over a 4-- no way.

Take my opinion for what it is worth.

 

[MissElizabeth]

Whitewave - I should mention that I got them from a private seller on LoupeTroop, so a return may not be possible even if it was my desire. So, there's definitely some incentive for me to like the stones I have. I also definitely didn't pay the price of ideal cut stones, since they are uncerted pre-sets and came with no proportions. Budget was definitely a factor in my shopping.

Now I feel a definite sense of self-doubt about my decision to purchase this set, though I really do enjoy them in person.

 

[whitewave]

Oh, right, yes, my first engagement ring is uncertified and a I1 clarity and I still very much enjoy it. Sorry if I added doubt!

 

[marksbcss]

Hi MissElizabeth,

Properly used as a rejection tool, the HCA can let you weed out probable bad performers without actually looking at diamonds. If you are searching through many, many diamonds, this can save you a lot of time. But this is only the first step. Now you need to use other tools (Idealscope, ASET, etc.), and actually look at the 'acceptable' stones.

But remember, the HCA also has limitations. (See: https://www.goodoldgold.com/consumers-guide-hca) It makes assumptions about diamonds that may result in a false negative (rejecting a good looking stone), or a false postive (great HCA score, crappy looking diamond)... Above all, if you already have a diamond in front of you, you shouldn't need an HCA score to tell if it looks good or bad.

You said your studs "show up beautifully in person". So keep them clean, and they'll always look bright (like you just changed the batteries . And enjoy them!

 

[Tophat1]

If they are uncerted, where did you get the data?

 

[MissElizabeth]

If they are uncerted, where did you get the data?

Tophat - all of the data was provided as part of an appraisal I had done. The appraiser was kind enough to go into the proportion level of detail for me after I asked some follow-up questions to the basic appraisal info.

 

[Tophat1]

Ah, ok. I would take the specs as approximations then, which means the HCA scores could be widely different. I'm not an expert, but an appraiser trained to do this like a cerification lab would be, and even if he was, I'm assuming the stones were evaluated while mounted and that would impact the ability to get a precise result

That being said, it sounds like you have some gorgeous 60/60 stones (which is my preference for earrings)