The acid test tells you if it's silver or not, but it doesn't tell you if it's 900, 925, 950, or 999. So how do you determine that? And how can they tell that the Maple is 9999 and the Eagle is just 9995, how can they test that?
If you really need to re-check a certified Mint metal content.$$$$ and this link will help ya->. http://www.worldoftest.com/goldtester.htm
The larger problem is how to detect the difference without damaging the specimen. If one is testing the assay of the metal used to make the coins, micro-quantitative chemistry can do that with little problem, thus the mints can do checks before minting. If the object is made and one doesn't want to take a sample off, usually X-ray Diffraction or similar type of analysis doesn't leave a visible effect, but these typically produce a .01 range for small units ( Approx. $20-30, 000) and .001 or better in the $100,000 + range. That is why one should only buy 90% + precious metal in a recognizable form. Truly, any higher content than .99 will not matter if processing as melt. Craiglist has had mine consultants that run a XRD test for $100 each on metal samples, but he uses the lower resolution machines.
I was in a coin shop recently and one of the customers was buying a slug that claimed 0.9999 purity just for fun.
I doubt he will ever be proven wrong. I really do want one of those devices! Even the less expensive ones, or some of the machines BadThad has available ( envy), but Peter doesn't pay that much ( any ).
Id love on! Especially since I mainly deal in bullion. But those things are way too much! There's a local jewelry store that laser tests any metal for a flat $10!
