AGS 000 but out of "the zone" on HCA?

[milton333]

So, I'm puzzled here. Looking at a diamond that is an AGS 000, and a branded stone by a vendor I've worked with before.

Here's the HCA, purporting to show a result outside the AGS box. I think I trust the AGS cert and the vendor more than the HCA, here, but any thoughts?

61.7% depth
56.1% table
34.9 degree crown
40.9 degree pavilion

 

[diamondseeker2006]

All I know is that you don't put AGS0 stones into the HCA at all. 1.8 is fine regardless.

 

[0-0-0]

My understanding is that the HCA still plots the outline for the old AGS proportion based cut grade. The current AGS light performance based cut grade has a bigger and fuzzier outline.

 

[yssie]

Within ID cut grade on AGSL proportions charts http://agslab.com/docs/pbcg/AGSLProportionCharts.pdf

Proportions charts are misleading wrt AGS stones w/ Light Performance analysis reports - stones with proportions outside the ID range on the charts can make AGS0 grade, stones with proportions within ID range on the charts may not make the 0 grade, since it's not strictly proportions-based - the stone is scanned and light return judged by their proprietary ray tracing programme (PGS). I don't know how Garry determined those outlines, if they are/were based on a specific set of charts - may want to ask him directly, or maybe someone with more knowledge will have more info for you.

 

[kenny]

If it's my money I'd not buy it.
Find another that every tool blesses.

 

[milton333]

While I don't want to post too much info on the stones I'm considering, would you buy:

1. Option 1, above, AGS 000 I VS2 7mm diameter round

2. Option 2
GIA xxx H VS2 6.75mm diameter round
HCA score 1.0
(I've seen pic and had gemologist say it looks great) - This one is ~ $1,000 less than Option 1
ETA: this is a virtual stone, I could request an IS but would be buying it through the vendor with my upgrade policy, and feel like maybe I should offer to pay the other vendor to do the IS?



3. Option 3
AGS 000 I SI1 6.9mm diameter round
Won't post HCA pic, but it's 1.3 and in midst of AGS box on HCA tool
More or less same price as Option 1, but may not qualify for upgrade policy, may need to sweet talk
IS is beautiful for Option 3

I'm trying to work within an upgrade policy, so have somewhat limited selections.

 

[Gypsy]

Idealscope image trumps all.

Here's a wonky AGS 0: http://www.jamesallen.com/diamonds/D-VVS2-Ideal-Cut-Round-Diamond-1371917.asp It happens.

I'm not saying the one you are looking at is bad, I'm just saying that it happens that not all AGS0's are as good as others are.

 

[0-0-0]

Agree with Gypsy that ASET/IS trumps all, unless you can compare the stones in person.

For a rough idea of how AGS 0 parameters changed over time: http://www.octonus.com/oct/mss/gia-ags.phtml

What mm are you upgrading from?

I would probably go with option 2. I don't find a difference of ~0.2 mm particularly memorable, so I would go with the cheaper stone and less color.

 

[milton333]

Upgrading from 5.97mm. Had hoped to reach the magic 7mm, kind of my "destination size." But I think 6.75 is still a noticeable size increase. I'm not super color sensitive, owned a J, so I think I could handle I, but my current stone is an H.

 

[milton333]

AGS light map for Option 1. Will ask for IS.

 

[JulieN]

It looks great, you do not need an IS. The box shows AGS 0 candidates, I assume that means that if cut with a high degree of precision, there is a certain minimum probability of getting a 0. So not everything in the box get a 0, and not everything out of the box can't get a 0.

 

[milton333]

IS and ASET on Option 1. Thoughts?

 

[yssie]

IS and ASET on Option 1. Thoughts?

Looks great, and the size difference will definitely be noticeable

 

[Gypsy]

IS and ASET on Option 1. Thoughts?

Looks great, and the size difference will definitely be noticeable

Agree.

 

[Dancing Fire]

Idealscope image trumps all.

Here's a wonky AGS 0: http://www.jamesallen.com/diamonds/D-VVS2-Ideal-Cut-Round-Diamond-1371917.asp It happens.

I'm not saying the one you are looking at is bad, I'm just saying that it happens that not all AGS0's are as good as others are.

yup,good example of one those flat top,big table,deep bottom half stone..