gxseries Posted May 31, 2008 Report Share Posted May 31, 2008 This is going to be a bizarre question to all - has anyone done one before? I vaguely remember someone here has done a mass spectrometry for their German African coins. I believe there is very interesting purpose for this as this can explicitly discriminate what type of metals were used as well as possibly tell the difference from a restrike and original. Link to comment Share on other sites More sharing options...
numismatic nut Posted June 1, 2008 Report Share Posted June 1, 2008 You may be on to something. I have heard about a process like this for gems. I'm not shure if the process would damage the coin. Link to comment Share on other sites More sharing options...
cestrin Posted June 1, 2008 Report Share Posted June 1, 2008 From my experience, I believe that mass spectroscopy involves shinging a light through and object and getting information based on that. In the case of gems this works because they are all somewhat transparent. The light allows for imperfections to be found. I don't know if this is the same sort of process used for coins but I'd imagine it wouldn't ruin the coin. Also, if you said it's for German African coins, try posting this in the World Coins forum and see if you get a response Link to comment Share on other sites More sharing options...
thedeadpoint Posted June 1, 2008 Report Share Posted June 1, 2008 X-rays are the answer, my friend. Shine a beam at the surface and the instrument can tell you the composition of the alloy. I use something called energy-dispersive x-ray spectroscopy to look at jades. An electron beam messes with the atoms in such a way that the atoms emit an x-ray. Each element has a signature x-ray and the detector counts the number of each type and tells you how much of each element you have in the sample. Quick and easy. Not too expensive either. If you're making a poster or a presentation for a coin show, you can probably find a local private lab that can run the coins through an instrument for you. I bet it'll cost ~$150 for a bunch of coins (including labor fees), but you'd get nice results! Link to comment Share on other sites More sharing options...
gxseries Posted June 1, 2008 Author Report Share Posted June 1, 2008 You see, there are interesting stories about Russian coins that I have been investigating and there were coins that were made out of cannon metals. The only problem is, they had no mintmarks and no clear way of telling apart from coins struck in other mints and it can be possible that they were made else where. A bit extreme and expensive way to tackle a problem like this but if the costs are low enough, I'm sure such studies can be very benefiting as well as interesting. Link to comment Share on other sites More sharing options...
thedeadpoint Posted June 2, 2008 Report Share Posted June 2, 2008 You see, there are interesting stories about Russian coins that I have been investigating and there were coins that were made out of cannon metals. The only problem is, they had no mintmarks and no clear way of telling apart from coins struck in other mints and it can be possible that they were made else where. A bit extreme and expensive way to tackle a problem like this but if the costs are low enough, I'm sure such studies can be very benefiting as well as interesting. If I were you, I'd find a local lab that has X-ray fluorescence spectroscopy or the method I mentioned. I'd bet good money there is one nearby. Ask them for a quote. Again, the only significant cost is the cost of labor. The machine and materials are cheap. OR, you could go to a local university and go to a materials science, chemistry, or history dept and see if anyone will let you use their instrument. They could be a co-author on your presentation and may have similar projects. Wouldn't take much investment on their part at all. Just make good friends with one of them. Try one of those. The worst that could happen is they just aren't interested or don't respond. Link to comment Share on other sites More sharing options...
Mark Stilson Posted June 2, 2008 Report Share Posted June 2, 2008 If you know anyone who works in metals inspection you can see if they would PMI the coin. I have brought out a couple coins to have them checked at the plant. It just takes a few moments. (BTW completely non-destructive.) Link to comment Share on other sites More sharing options...
Hussulo Posted June 2, 2008 Report Share Posted June 2, 2008 Robert Matthews offers a coin authentication service for British milled coins: http://www.coinauthentication.co.uk/index.html To undertake this he uses: "This includes an analytical balance with a density kit, a stereomicroscope, a Sigmatest conductivity meter, digital callipers, digital photographic equipment, modern IT equipment and crucially a well-stocked library of suitable reference material. I can easily access outside resources such as x-ray surface analysis, electron microscopy and spectroscopy and suitable literature and reference materials." Link to comment Share on other sites More sharing options...
hiho Posted June 2, 2008 Report Share Posted June 2, 2008 This thread really opened my eyes. Energy-dispersive x-ray spectroscopy, whoa. Thanks for the lesson deadpoint. I do own a small portable blacklight from back when I collected currency. Easy way to spot a repaired note. Link to comment Share on other sites More sharing options...
thedeadpoint Posted June 2, 2008 Report Share Posted June 2, 2008 If you know anyone who works in metals inspection you can see if they would PMI the coin. I have brought out a couple coins to have them checked at the plant. It just takes a few moments. (BTW completely non-destructive.) That's exactly what I mean! Glad to know that my idea is shared by others (I was waiting for someone to correct me I'm usually wrong). All of these methods are non-destructive. That's why you should use them instead of Mass Spec. Mass Spec. would have you somehow powdering the coin or somehow put it into solution. Link to comment Share on other sites More sharing options...
YeOldeCollector Posted June 2, 2008 Report Share Posted June 2, 2008 All of these methods are non-destructive. That's why you should use them instead of Mass Spec. Mass Spec. would have you somehow powdering the coin or somehow put it into solution. I always dissolve my coins to find out if they're genuine! Link to comment Share on other sites More sharing options...
henare Posted June 3, 2008 Report Share Posted June 3, 2008 I always dissolve my coins to find out if they're genuine! there's some monty python in this i'm sure Link to comment Share on other sites More sharing options...
henare Posted June 3, 2008 Report Share Posted June 3, 2008 OR, you could go to a local university and go to a materials science, chemistry, or history dept and see if anyone will let you use their instrument. They could be a co-author on your presentation and may have similar projects. Wouldn't take much investment on their part at all. Just make good friends with one of them. i wonder if it's still that easy ... i could see this sort of thing happening when i was at MIT in the 1980's-1990's ... Link to comment Share on other sites More sharing options...
Mark Stilson Posted June 3, 2008 Report Share Posted June 3, 2008 I wonder how much variance in metals for cannons and coins back then was acceptable or just the limits of metallurgy. A 57 nickel I had PMI'ed showed 73.82 copper, 26.71 nickel, .4 magnesium which is supposed to be 75 copper, and 25 nickel. Link to comment Share on other sites More sharing options...
Victor Posted June 3, 2008 Report Share Posted June 3, 2008 EDXRF has been used to analyze Roman coins for many years. About two years ago, I had 23 contemporary imitations analyzed. The science department at my university did the testing for free, but I was a grad student. Link to comment Share on other sites More sharing options...
YeOldeCollector Posted June 3, 2008 Report Share Posted June 3, 2008 there's some monty python in this i'm sure Link to comment Share on other sites More sharing options...
thedeadpoint Posted June 4, 2008 Report Share Posted June 4, 2008 i wonder if it's still that easy ... i could see this sort of thing happening when i was at MIT in the 1980's-1990's ... See you guys probably are a little more fun and intrigued by the coin analysis than the people here would be. I know a few professors that would be interested here but there are plenty that are too uptight. Link to comment Share on other sites More sharing options...
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