mogok
Shiny_Rock
- Joined
- Jan 20, 2004
- Messages
- 408
Hello,
Origin determination is only an opinion that the lab give as this is something very difficult to give especially if the stone was heated many times and all its inclusions are melted.
To determine the origin of the stone they compare the stone with their data and their gemstone collection. They study the stone inlcusions with the microscope and they also use advanced instruments like Infrared Spectroscopy, UV Visible spectroscopy, Raman Spectroscopy and RXray fluorescence. They compare these results with the datas they have from stones of the same given origin... At this point inlcusion identification and knowledge in geology are important as some inclusions are typical from some deposits.
But sometimes when a stone is clean, without inclusion either visible or microscopic, or if the stone does not present any specific that help to identify it without mistake from this or that mine, then its becomming really tough.
All this make you also understand that one of the major problems a lab will have to give origin in gems are their data... Are these data 100% sure? Well if the people from the lab went themselves to the mine to get the samples, may be but if they just get the stone from reliable sources in the trade, there are possible mistakes. And even in the first possibility if you get a ruby lets say from Mogok it does not mean that all the rubies from Mogok will looks the same: There is around 1000 mining operation in Mogok and the Mogok stone tract cover an area which is around 50km on 40km with a very complicated geology... And of course I dont spaek about new gemstone deposits.
Origin determination is not as easy as clarity grading.
Its an opinion.
Some very serious labs like Gubelin have excellent data but they can make mistakes, other labs less serious but more marketing are more guessing or just give to their good customers the origin that will make them happy if the stone is a border line case (I mean a stone that will pass for many as from here or there, for many stones, it is very difficult to make the difference between Vietnamese and Burma as an exemple but as the difference in price is very important so, for a good customer, they give "Burma" thinking that whatever: Who will dare go against the opinion of such a powerful laboratory name?
Origin should not be related to quality, but its linked to romance...
Hoping to have answered correctly.
Origin determination is only an opinion that the lab give as this is something very difficult to give especially if the stone was heated many times and all its inclusions are melted.
To determine the origin of the stone they compare the stone with their data and their gemstone collection. They study the stone inlcusions with the microscope and they also use advanced instruments like Infrared Spectroscopy, UV Visible spectroscopy, Raman Spectroscopy and RXray fluorescence. They compare these results with the datas they have from stones of the same given origin... At this point inlcusion identification and knowledge in geology are important as some inclusions are typical from some deposits.
But sometimes when a stone is clean, without inclusion either visible or microscopic, or if the stone does not present any specific that help to identify it without mistake from this or that mine, then its becomming really tough.
All this make you also understand that one of the major problems a lab will have to give origin in gems are their data... Are these data 100% sure? Well if the people from the lab went themselves to the mine to get the samples, may be but if they just get the stone from reliable sources in the trade, there are possible mistakes. And even in the first possibility if you get a ruby lets say from Mogok it does not mean that all the rubies from Mogok will looks the same: There is around 1000 mining operation in Mogok and the Mogok stone tract cover an area which is around 50km on 40km with a very complicated geology... And of course I dont spaek about new gemstone deposits.
Origin determination is not as easy as clarity grading.
Its an opinion.
Some very serious labs like Gubelin have excellent data but they can make mistakes, other labs less serious but more marketing are more guessing or just give to their good customers the origin that will make them happy if the stone is a border line case (I mean a stone that will pass for many as from here or there, for many stones, it is very difficult to make the difference between Vietnamese and Burma as an exemple but as the difference in price is very important so, for a good customer, they give "Burma" thinking that whatever: Who will dare go against the opinion of such a powerful laboratory name?
Origin should not be related to quality, but its linked to romance...
Hoping to have answered correctly.
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