Thank you, this is great info. It’s very hard in that region to associate gemstones or beads with any specific culture beyond the neolithic (where there are some roughly distinct shell beads, I believe). It was a comparatively highly populated/settled region with tremendous change since the early Bronze Age. But the mineral characteristics of those sources are very intersting and helpful, thank you!
Thank you. I will also scout this forum
for labs that might be able to help at a reasonable cost.
I too will become the owner of these two books! thank you for the suggestion!
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Woah, amazing resources. Thank you!
Hello PaulB36648!
I haven’t been on this forum in a while and read with great interest this thread about your proposed research into turquoise jewelry (and other gems/minerals?) from ancient sources. I’m just a practical gemologist and gem cutter, so I’m not a lot of help in this matter myself. However, there is a lot of analysis of specimens that could be done, as Steve Hata points out. While tests are often destructive, some are not and others require only small samples. I think you need more input from some gemologists and geologists who are familiar with the testing procedures and the kinds of numbers you could get from them. If someone developed a database of the composition and appearance of found objects from various archaeological sites, it could become a great resource for researchers. I hope I am making sense here.
There is one fellow you should talk with, L. Bruce Jones. Bruce had an early and distinguished career in lab gemology before going into building same submarines. You can find him on Facebook. He knows all of the current sophisticated and expensive lab instruments and what kind of info can be gleaned from each of them. He can possibly assist you in determining what tests to use and what each will tell you.
If I were you I would also talk directly to GIA in Carlsbad. Their research journal is one of the main organs for research into gemstone parameters and their lab is one of the most sophisticated in the world. While they focus on gem ID and documenting new finds, I think they might find basic research into the gems of antiquity quite interesting. Possibly they would associate on some research project and even be able to suggest how to get funding.
Just throwing this out on the forum for public discussion. I’ll also try to DM you directly.
Hope this helps,
royjohn
The use of a mass spectrometer present in some university laboratories and by measuring the ratio between stable and unstable isotopes can estimate the age of a rock or mineral, even a gem.
dr. Piero Manuelli FGA Gem-A
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Hello,
There is a facebook group “Lets Talk Quality Turquoise” that has members around the world, some sciency people and and some experts in turquoise. I think the ability to determine source of a stone requires in person examination, but the diagnostic criteria you are after might be the kinds of tests that GIA does.
Some people can determine where a stone is likely to have originated if its specific mines they are familiar with. But what smart gemologists will tell you is its not possible to do that in a picture. And turquoise experts will always offer an opinion with the caveat “only the miner knows where it truely came from”.
Try the FB group or the one on Turquoise Formation.
And if you have not discovered it yet, Mindat is a major database online of minerals and localities, sometimes with pictures of the localities & material, and good descriptive material.
P.S. I worked as an archaeologist early on in my career and was trying to do pottery origin analysis of meso american stuff based on the clay composition to map trade routes, so I appreciate the scope of your inquiry.
-tina
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Do you happen to have, or can point me to, a pic?
Thank you very much for the reply, it is great info. I’ll reach out to the contacts you suggest, thank you!
just the one I previously posted. I do not currently have any, although I do want to get some more when I find it!
laser ablation mass spect is only minimally destructive. However, unless university supported (grants) the cost of running a sample is prohibitive. I was quoted up to $6K per sample for whole rock analysis to do geochemistry, including isotopic analysis. That was just for the standard uranium//lead ratios, Sr/Rb and eNd ratios.
re mass spect: sampling both turquoise and matrix via laser ablation mass spect will give you a definitive answer as to the composition and source of the turquoise or any other stone… IF you can find a cross reference to same in the gemologic/mineralogic/geologic literature. Research Gate is where you can find all of this stuff, but you have to have had published a scientific paper to gain access. I had two publications that allowed me in.
Thanks, I missed this. Very helpful.
How far has your research into your fascinating and potentially ground breaking research gone so far?
I would suggest taking your samples to expert gemologists in turquoise first for visual inspection and nondestructive testing. You will need to get several opinions. I would be surprised if the opinions converged. Ultimately, the geologic origin and provenance can only be determined by trace element signatures and isotope ratios… the former can be obtained by electron microprobe which is very minimally destructive. the latter, by laser ablation mass spect… costly unless supported by grants. If you are doing this yourself, you need to approach academics. Someone should take interest. Full research projects have to be supported by grants. Getting grants without academic credentials is impossible.
Thanks for the encouraging note. I am currently working with some exceptional people who have helped a great deal. My biggest gap right now is with the geology/mineralogy. The help I need is quite specific, and it’s been a bit difficult to find the right person/people. An expert gemologist would also be very helpful on a number of levels, regardless of any possibility of definitively tracing specific gemstones to a singular point of origin. If you know of any, I’d be grateful for a referral. Thanks!
it depends on where you live. You could try and contact the turquoise museum in Albuquerque, NM… if you can’t go there in person they could have you ship it there for examination. [
The Turquoise Museum
[image]
The Turquoise Museum
https://turquoisemuseum.com
](https://turquoisemuseum.com/)
Turquoise Museum · Home · Joe Dan’s Corner · History and Mission
Note that this a commercial outfit… you will get charged a fee.
If you are anywhere near a university with a geology department, start there also. You might find someone who can refer you on. Another option is starting at a local jewerlry store. The proprietor may have ideas as where you can send your material for the kind of examination you are looking for.
Determining provenance will require analytic methods. You mentioned that you have to find specific help. What specific help is it? Please throw it out to the group and see if anyone can send you in the right direction.