AIGS terminology - probably origin?

[haagen_dazs]

I was just browsing through some of gemwow''s inventories and I had the chance to look at some AIGS grading reports.
I suppose those are the official AIGS reports (have never seen one in real life)
They are called "gemstone identification - ereport"

1) Is this considered the grading report? or is it just a lean version of a real proper report?

2) Something kind of struck me as I was looking at the report. One of the report inputs is "PROBABLY ORIGIN"

Now even an institution doesnt 100% know where the stone comes from, how does one even trust anyone else when they claim a certain origin location? How is an origin "tested" by AIGS (or any other labs) ? Is it merely a word of mouth thing? How does this all work ?

 

[morecarats]

Every geological formation has unique conditions and gems of a specific variety from a particular location are thought to have a ''fingerprint'' that can in principle be identified.

To do this, a lab has to build a database of physical and chemical characteristics specific to each gem variety and location. It requires analysis of a large population of samples. Most labs that do country of origin reports will do so only for a small number of gem varieties, typically ruby, sapphire, emerald and perhaps alexandrite. The Gubelin lab in Switzerland is the pioneer in country of origina analysis, due to Edward Gubelin''s lifetime of work on the analysis of gemstone inclusions.

 

[empress]

They are assessing inclusions in the stone and comparing them to known inclusions from specific countries (and maybe mines) and determining, based upon those inclusions, the probability of the stone being from that location. The only way to know "100% where the stone comes from" is to get it there yourself.

 

[haagen_dazs]

you guys are awesome
thank you for enlightening me