How accurate is a Sarin Machine?

[diamondsbylauren]

Hi everyone- I have had sarin reports drawn- but I never actually used the machine personally.
I was wondering if there are any experts- experienced in using a sarin - or OGI- machine, the could give us an idea what kind of "repeatability" the results show.

That is to say- if you tested the same stone twice, would the results be identical?

 

[belle]

david,
obviously i am no sarin expert, but i like to post in your threads anyway

it is my understanding that sarin measurements can be off by up to .2 on any given angle. if you ran the same stone on the same machine more than once, i believe you will get very similar results.
if however, you ran the same stone on two different machines, you may get a wider varience. this due to the fact that each machine is calibrated seperately.

 

[Kaleigh]

belle, How do you know all that, I''m impressed!!!!!

 

[belle]

you should see what i can do with an automatic sewing machine and 5yards of silk damask!

now that''s impressive

 

[strmrdr]

It also depends on which ogi and which sarin machines.
The latest highest end version of both are very good with maybe a slight edge to the sarin.
Id expect minimal differences run to run with more differences between the 2 machines readings for the same diamond.
The low end scanners from both are pretty much a joke these days.
Jon at gog is the person Id talk to for more info on them.

 

[diamondsbylauren]

This all relates to another thread.
https://www.pricescope.com/community/threads/are-the-hearts-arrows-cut-diamonds-just-a-fad.30812/page-6=

I did a little research-as well as having 2 Sarin Reports done on the same stone.
The results were, indeed, very close to one another.
So- the answer to my own question is- YES- results are repeatable if one test the same stone on the same machine twice.
As Belle pointed out, the main problem is different machines caligrated differently.
Surely the Sarin at the GIA, or the diamond club in NYC will be properly calibrated.
It''s not possible to make the same statement for a large percentage of the other machines out there.

 

[Nicrez]

David, I also believe that the program used has a bit of an effect. Obviously rounds stones are more accurately measured than any other shape. Hearts could possibly be the worst, but not sure? Horseheads maybe..?

Sometimes the Sarin of the same stone on the same machine will vary like Belle said about. 2. usually the girdle is dead on in range, and the measurements as well. But angles are always tough, as they vary. I think some Sarins give you EACH angles, whereas others just give you the averages.

Will someone please tell me when they get a very accurate shaped stone Sarin?!

 

[Rhino]

Hey Dave,

Good to see you experimenting with the Sarin''s. I''ve owned the Sarin BrilliantEye for a few years when it first came out. It''s an "ok" machine, certainly better than nothing but the results were not always as accurate as I like. I then got the DiaScan which was better but then figured... what the heck... and we gave that back and got the DiaMension. The results on our DiaMension are as precise as it gets and are very repeatable. The only scanner that may top it would be Helium. I''ve seen the scans and the models it produces and I am extremely impressed with what i''ve seen so far.

Not only this but I also have a way for checking, if there are any discrepancies between our Sarin measurements and that of AGS (since they do supply basic proportion data on their reports)or any scanner for that matter. Ie. I am very familiar with optical results of certain proportion combinations so when I see any discrepancy between our Sarin and another machine I can tell immediately which Sarin would be correct by the optical results produced by the angles (in most circumstances). If you''d like to see more on how I do this I can gather the graphics and give you an example if you like.

We also have OGI''s scanner here as well. Their latest version with all the software to accompany it. It does produce nice reports but at the end of the day I would have to side with the accuracy of our Sarin. Both have pluses.

One of the real tests of an accurate scanner is its ability to resolve facets that are very close in angles which are adjacent to each other. For example if you take a stone that has upper girdles less than 40 degrees whose bezels are in the mid 34.x or 35.x range that are coupled with upper girdle angles like this ... it is very difficult for scanners to differentiate and resolve between the facets. Here''s a scan from an OGI on such a stone. Only 3 upper girdles were resolved with detail that is not that good.

Note that these upper girdle angles are not common and are akin to 8* types, WF new line and certain unbranded H&A''s we feature.

 

[Rhino]

Here''s a scan of a similar stone with upper girdles under 40 degrees with the Sarin DiaMension (uses 3 seperate lens depending upon size of stone). Note how all the upper girdles are clearly resolved and differentiated from the bezels. Their shapes of the facets however are a little off. So it appears that there are misshapen facets on this stone when in fact they are not. It''s the scanners inability to *read* the stone however this is the best we have found and been able to produce. I would also note that it''s only with stones like this that the scanners have this problem with. Typical upper girdle angles are generally in the 40-43 degree range and both Sarin and OGI scanners have no problem resolving all the facets in those circumstances.

 

[Rhino]

Date: 7/21/2005 8:54:56 PM
Author: Nicrez

I think some Sarins give you EACH angles, whereas others just give you the averages.

Will someone please tell me when they get a very accurate shaped stone Sarin?!

Correct Nicerez. Depending on the software you can either get all facet measurements or only the averages. Most people in the industry are using the old software and don''t bother upgrading.

We DO indeed have a very accurate Sarin. We have also tweaked it to scan slower and more accurate for the purpose of models. If you compare our Gem Advisor files and look at the H&A views produced by the model and compare them with the actual photographs, in those stones that we scanned at the slower speed/more accurate mode you''ll see the views produced by the model are, in most cases spot on with the photography. That is another good test for a scanner and its modeling abilities as well.