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"You can't trace it back to the origin, as long as it's been melted down." Allow me to introduce you to the concept of Isotope Fingerprinting http://en.wikiped
by olefoo 15y ago
"You can't trace it back to the origin, as long as it's been melted down."
Allow me to introduce you to the concept of Isotope Fingerprinting http://en.wikipedia.org/wiki/Isotope_fingerprinting http://en.wikipedia.org/wiki/Isotope_fingerprinting
So even melting doesn't necessarily prevent tracing.
- daniel-cussen 15y agoI'm not sure you can do that with gold because there's only one stable/naturally-occurring isotope, and the most stable other isotope has a short half-life of six months. Labeled gold's radioactivity may be a give-away.
- foob 15y agoWhat about trace element analysis?
- daniel-cussen 15y agoThat you can do, but it's less effective because separating and purifying different elements is much easier than doing so with different isotopes.
- sycren 15y agoAre you suggesting adding small impurities to the gold and then measuring them at a later stage? Surely that would be a very easy thing to change.
- foob 15y agoYou don't need to add the impurites, they're already there. Metals have fairly distinct patterns of impurities depending on where they were mined from and it's basically impossible to entirely remove them. If you expose a sample of metal to a large flux of neutrons (usually in a reactor) then the nuclei of the various elements in the metal will absorb neutrons and then decay. The products of these decays can then be analyzed to work out the composition of the metal even if an impurity is very small. This type of analysis has been common for a very long time now. An example of a current use is determining the country of origin for controlled metals like plutonium and uranium. There are ways to get around this kind of approach (by adding impurities, not removing them) but I felt like mentioning it because it makes a lot more sense in this context than isotope fingerprinting.