AGS/Sarin accuracy

[stepmars]

Why would there be (minor) variances between an AGS certificate and Sarin report? I thought AGS used Sarin data to compile their reports. Which is more accurate?

AGS:
Depth % 60.9
Table % 54
Crown angle 34.9
Pavilion angle 40.8
HCA 1.4 (EX, EX, EX, VG)

SARIN:
Depth % 61
Table % 54.4
Crown angle 35
Pavilion angle 40.9
HCA 1.8 (EX, VG, VG, VG)

 

[openhelix]

Yep, that's perfectly normal. Sarin machines (even the ones used by AGS) aren't 100% accurate, just over 99% accurate so you'll see slight differences between makes of sarin machines, or even calibration, I'd imagine.

 

[CaptAubrey]

i would go with the ags measurement. the accuracy of sarin readings is connected to the expertise of the person using it.




sarin machines are not perfect, but they are used by gia, ags, hrd, egl, and diamond manufacturers and wholesalers around the world, so presumably they're reliable enough.

 

[stepmars]

I think i've just learned an important lesson. I've been placing a lot of emphasis on HCA scores in comparing diamonds but if these acceptable small variances can result in a range of 1.4-1.8 then maybe I shouldn't be overly obsessive. I must admit to still being a little puzzled. If the range had been say 1.4-1.5 or if the dimension variances had been more pronounced it would be easier for me to understand.

 

[openhelix]

The HCA really isn't a black and white tool. It will give you a general idea, however some of the most beautiful stones I have seen scored poorly (~2.5) on the HCA and I've seen some lifeless stones that scored well (~1.5). If you want to use it to sort out bad stones, I'd take everything that scores between .5 and 2.25 and throw it in the good column, then use a more granular method to take it from there (while disregarding previous scores).

 

[mdx]

Hi Stepmars
I would not worry too much about the differences; there is no visible difference between a HCA 1.4 and a HCA 1.8.

I do however understand your frustration as our Sarin has slight a difference on the pavilion calculation when compared to the machine used by our local Lab (DCLA).

A lot of our Ideal Cut stones are cut for fire and so are often around 1.8. It’s sometimes a bit embarrassing when the Lab measurement turns up a score of 1.8 and our machine a 2.2 but we live with it, its no big deal. The advantages of using Sarin technologies are far greater than the small tolerance deviations.

Both the HCA and Ideal Scope are excellent tools, you don’t need to be worried by small score differences.

Johan

 

[valeria101]

The instructions for HCA use say that those diamonds with scores over two pass the test. Variances between scores above this threashold are not mentioned and it is not a simple thing to determine what variation of HCA in this 'accepted' interval is is 'significant' and what is not once visual impact as well as errors are considered.

The stone you have seem to have passed the test and this is as much as the HCA can say.

If you want an even more precise selection, some direct tests should be done on the stone (Ideal SCope, Brilliance Scope... or such).

 

[69gm]

i think the important thing to keep in mind is that there is no "perfect" way of measuring something like a diamond. "beauty in the eye of the beholder", and all that.

you should just use these numbers to help guide you in the right direction. in the end, only you and your fiancee will look at a box of 100 similar diamonds and find one that just seems to catch your eye and call out to you. it may not have the super numbers you think you are looking for, but if catches your attention, that's the one!

i know finding the right diamond can be a daunting task and i wish you well. just don't go too nutso over it. just find one that you know you will be happy with. otherwise you could spend the rest of your life looking for the "perfect" diamond.

hope my thoughts help.

 

[stepmars]

"...you and your fiancee will look at a box of 100 similar diamonds..."

my wife may have something to say about that! thanks to all. the advice is greatly appreciated.