testing the provenance of gems and plain old rocks is possible but is very expensive… laser ablation inductively coupled plasma mass spectrometry (LA ICP MS) is so sensitive that it can almost count individual atoms and profile a mineral sample down to parts per billion of trace element constituents. It can also separate isotopes and is the only technique that can do so… academic and commercial labs charge $100/hour on average to run samples… prep time and repeat runs to confirm will add up… I was quoted, ten years ago when I was interested in doing research on some unusual rocks from Hawaii, 2K per sample… to be scientifically valid, at least a dozen rocks would have to be analyzed… trying to do a research paper as a non professional would have cost three times the cost of running 6 -12 samples… it was cost prohibitive. I have a number of papers on the topic of these rocks, but there’s still a lot of controvery surrounding their petrogenesis… non traditional isotopic ratios might be an addition to what is already known…however cost prohibitive… only way I could do it would be to get a degree in geology and get into an advanced degree program… thinking seriously about doing so…
just to finish up: the age of some of your rocks can be dated, but probably not for agates and other quartz stones… unless the quartz is in crystal form with inclusions containing fluids and trapped mineral inclusions, dating quartz by uranium/llead, neoymium/samarium, rubdium/strontium and potassium/argon and argon/argon dating cannot be done… quartz does not trap radiogenic elements… optical luminescence and thermoluminescence can be used to date quartz and man made ceramic material up to 1 million years old… cannot be used to specimens that have been dug up and exposed to ambient sunlight… samples have to be retrieved and kept in the dark until tested… your quartz stones and agates could be 100’s of million of years old or even a couple of billion… beyond that technique… only radiogenic isotope ratios can date geologic time materials. quartz unfortunately is barren of those elements.
Steven, again thank you.
I have books and have pored over them for four years. Having worked for 4 and 1/2 years with scientists at a Primate Research Center and having been responsible for inputting and proofreading many, many abstracts submitted to the International Aids Conference which my boss and I were responsible for, I surprisingly can and do read abstracts for all sorts of information and have no problem understanding the gist if not the chemistry behind it. I hated chemistry in school and was always an english person.
The Missouri branches into the Pearl River, which branches into the Bogue Chitto. Also there is the Tangipahoa River where much of this stone comes from, in general.
When I first began finding these stones, I learned very quickly that it was not easy task to get anyone to look at them and/or positively I.D. them.
So, I began to teach myself, not having to work anymore either.
Thanks again for sharing all your wonderful knowledge.
Okay. I know what the problem is for sure. My perfectly flat and polished is not refractive index required perfectly flat and polished.
I polished the hemicylinder again with cerium oxide and tested my tried and true citrine. The green line was sharp, very green and very obvious. I don’t even have to move my head. It’s just there; 1.54-1.55.
When I look closely at my stones, though they are a huge improvement from when I found them and have polished them, they have very small “pockmarks”. It’s not from me. They just haven’t been polished out enough.
I know polishing wheels come in different make-ups and grits (I’m assuming), so though I have an arsenal of stone equipment, I see I’m going to have to buy yet more.
Once it is flat and polished, it’s a piece of cake. Thanks.
primate science is still science, scientific methodology is the same for any and all of the sciences, be it primate behavior or nuclear physics… I am also retired so I can devote time to subjects that were not within my scope of practice as a non professional rock enthusiast. However, I started reading on isotope systematics, magmatic systems and differentiation long ago as a hobby…I also learned a lot from being a hobbist jeweler… I realise that if I do decide on formal training I will have to start from scratch as a non traditional student. Despite having taken 3 semesters of calculus, I did not go on to study multivariate analysis and matrix operations, essential for n-dimensional calculations… when I went to undergraduate school 50+ years ago, there was no such thing as AI and computed modelling… same goes for three semester of physics…I did take some inorganic and organic chemistry as a requirement for an advanced degree in my field… the principles of radioactive element decay and dating, isotope systematics and element and isotope partioning are well know to me, but the devil is in the details and I’ve forgotten the details… sitting in on the lectures at the geochemical society meeting, I can follow along the research and arguments, models with some difficulty… but doing that kind of science is beyond my capabilities… however, anyone who is interest in rocks still needs to gain some background in the earth sciences… it’s interesting in it’s own right but makes for practical knowledge that allows one to evaluate both pretty rocks and gemstones more carefully… identifying them is not easy, provenance tells eveything but determining provenance is not easy either… in many cases it’s impossible… without high tech eqiupment such as LA ICP MS, SIMS, EMPA… which doesn’t necessarily give you the answers either… it can give you a range of answers… listening on the lectures is listening in on the work done by others…it offers another learning opportunity and insight into how advanced technology has impacted all of the sciences including earth science…
the point is life long learning, simply for the joy of it… other friends of mine who have retired do nothing other than shopping, eating out, going to the movies and “enjoying life”… those who have done that are losing their cognitive skills quickly…the brain needs exercise too… not using it leads to losing it all faster… I am at an age where dementia threatens my demographic cohort… use it or lose it!
The RI of diamond will not be readable on a refractometer. The limit is 1.81 at the very best. The RI of diamond is above 2 easily
Also there are many articles here on using the different equipment to identify stones. Like a lot of articles. Check and see what you can find that helps!!
you are correct sir!. RI limit it 1.81 as you mentioned, diamond is 2.42…other methods have to be used.