HCA 2.4 to 1.2 on same diamond

[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/

 

[Garry H (Cut Nut)]

Well that is interesting.

As I expected - badly callibrated Sarin or Ogi.

Or dirty stone, poor operator etc.

I modeled it in Diamcalc whichh is very precise and with the given depth % - the stone has a shallower combination than the proportions suggest.

I am sure the stone is under 2.0 HCA

 

[JohnQuixote]

OSU, I thought you had seen my reply in the thread you posted in RockyTalky, but perhaps not.

I've pasted my reply again, and here is a link to your RockyTalky post.

- - - - -
Hi OSU.

I believe you may have typo’d the Table% from our Sarin.  It should have been 55.3% not 53.3%, correct? (You went back and corrected this)

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 great tool, but sometimes penalizes steep stones more than we'd like to see.
- - - - -

After seeing Garry's model it appears you now have four choices. Our Sarin and the AGS grading report agree on one set of numbers. The jeweler's Sarin and Garry's estimation are closely matched to another (slightly different) set of numbers.

Our assessment that this is a beautiful stone was made with Brian Gavin's eyes, which I trust more than any plug-in computer assessment. As mentioned, we will often see a stone the HCA thinks is too deep which we consider as beautiful as many that receive <2.0 ratings. However, if what you're really seeking is the under 2.0 "blessing," the inventor of HCA just told you it is

Short answer... No worries.

 

[Garry H (Cut Nut)]

Date: 1/29/2005 6:26

5 PM
Author: JohnQuixote
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.

Correction John, OctoNus Helium is far more accurate than any Sarin.

After seeing Garry''s model it appears you now have four choices. Our Sarin and the AGS grading report agree on one set of numbers. The jeweler''s Sarin and Garry''s estimation are closely matched to another (slightly different) set of numbers.

I do not think my numbers are at all close to the retailers - have another look - I had to make the pavilion very shallow to make it match up - this says that all the results indicated the stone was deeper / steeper than it actually is.

Our assessment that this is a beautiful stone was made with Brian Gavin''s eyes, which I trust more than any plug-in computer assessment. As mentioned, we will often see a stone the HCA thinks is too deep which we consider as beautiful as many that receive <2.0 ratings. However, if what you''re really seeking is the under 2.0 ''blessing,'' the inventor of HCA just told you it is

Ageed

Short answer... No worries.

 

[JohnQuixote]

Date: 1/29/2005 7:35:17 PM
Author: Garry H (Cut Nut)

Correction John, OctoNus Helium is far more accurate than any Sarin.

I'm aware of Helium, but the major labs still use Sarin (as do we). I did not think Helium relevant to this situation - unless you know of a helium scanner near OSU Cowboy's hometown that can be used.

I do not think my numbers are at all close to the retailers - have another look - I had to make the pavilion very shallow to make it match up - this says that all the results indicated the stone was deeper / steeper than it actually is.

I was not implying that they were identical. Correct me if I'm wrong, but since our numbers match what is on the grading report your numbers are closer to the jewelers. All of your pavilion info is significantly closer. Your table% & crown height numbers are between ours/reports & jewelers.

OSU - Garry and I are wont to split hairs.

 

[OSU COWBOYS]

I do believe it is under 2.0 HCA. Before I had the stone set, I had them do a Gemex brilliant test done and I got very good readings. I dont have them handy with me because I am waiting for the results from gemex to send them to me in paper. I do know that I had two very high readings out of the three. I did pick up the final ring set and I LOOKS GREAT!!!!!!! I am VERY PLEASED on the way it looks and it is beyond my expectations. Thanks to Whiteflash I got a wonderful diamond and I cant wait to propose! Thank You all for your help and input.