Can different sarin reports be different? HCA from 2.4 to 1.2

[OSU COWBOYS]

I have had two sarin reports done on my stone. One was from the the online dealer and the other is from local jeweller. The dealer sarin gave me a 2.4 on HCA and the local jeweler, who is setting my stone because i bought the setting from them gave me a sarin of a 1.2 TIC on the HCA. Here are the specs.

Online dealer where I bought the diamond Local Jeweler where I bought setting
diameter: 7.28 7.27
crown angle: 35.2 35.0
crown height: 15.9 16.0
Pav angle: 40.9 40.7
Pav depth: 43.2 42.8
culet: .5 .9
Table size: 55.3 54.5
total depth: 61.9 61.8
girdle thick: 1.7-1.9 1.0-1.7
HCA: 2.4 1.2 TIC

I dont know if their are sarin machines that produce different numbers? but the numbers are close but not same. As you can tell the HCA is different. What numbers are the best to go with . I would have thought that the dealor would give me better numbers than the local jeweller. So did I get a better diamond than I thought???????

Gary (cut nut) looked at my sarin at this post (below) and told me the sarin was better than it said because of my ideal-scope image. What do you all think?>>>>>

https://www.pricescope.com/community/threads/ideal-scope-image-again.23251/

 

[JohnQuixote]

Hi OSU.

I believe you may have typo’d the Table% from our Sarin.  It should have been 55.3% not 53.3%, correct?

Several thoughts...

1.  If there is a discrepancy the numbers on the lab report are to be considered most authentic.  Since this is an AGS stone, you can match all of them up.  I did a comparison and it looks like our Sarin matches the grading report.

2.  The Sarin machine is the current best technology available for getting measurements on a diamond. The generally acknowledged variance is .2 but in some cases it can range a bit more.  If you get a reading on one machine and using the same diamond get a reading on another machine, you will have two slightly different set of measurements.  Which one is correct?  Good question.  Before we had the Sarin we were doing it by hand with a micrometer and table gauge.  Other technologies will one day replace the Sarin.

3. On first blush it appears that something may be wrong with the calibration of your jeweler’s Sarin.  It calculated diameter (the number you gave) smaller than ours, but then calculated the stone as shallower.  For similar mass a smaller diameter should have resulted in a deeper stone.  The culet numbers are suspect. Do you know which version of the Sarin the jeweler has?  There are smaller models, the Brilliant Eye, DiaScan and DiaMobile.  We have the larger DiaMension which has been reliable for us.

4. In general, I suggest an independent appraiser is always preferable to a jeweler for verification for reasons of objectivity.  Of course, this jeweler might be your friend in which case never-you-mind what I just said

5.  The good news:  Either way you look at it, your diamond has great measurements.  The HCA is a nice tool, but it penalizes steep stones more than we'd like to see.

Hope this elaboration is good information!

 

[Regular Guy]

Looking at the data piece by piece (HCA is a composite calculation, one step removed), I note that it''s been reported there''s predicatable variation in sarin data by 2/10 of a degree, and your two sets of data is completely consistent with that that....except for the culet. My guess is that there are some outlier culets that will present variation in an HCA score, which why Garry includes it, but based on at leasta couple of dozen runs at the HCA, I''ve never seen a culet variation change the final numbers.

Since the two reasonably different sets of data provide different HCA''s, ordinarily it might be desirable to take a third bite. However, sounds like you got that already, as you''ve well documented from your link to your earlier post. Sounds like you''re in good shape.

 

[OSU COWBOYS]

yea, it was a typo jhon,I corrected it. thank you

 

[WinkHPD]

I had the 5k version of the Sarin machine for a short while. I could put the same stone on it ten times and get AGS grading from a O proportion grade to a 5 proportion grade. I am told that the 25k version is better but still not consistent. I returned my Sarin machine, and will wait until they make something that gives me a repeatable grade every time I use it on the same stone.

Wink