Electrum, since the gold-silver alloy series is a solid solution, should be homogeneous, but it is possible that cast materials may show some segregation, but I have only really observed that as far as I recall in materials with a little copper in them, then with more copper, they can be wildly out of equilibrium, otherwise we expect a solid solution. Useful information can be obtained from the electrums by etching in potassium cyanide/ammonium persulphate mixtures as grain boundaires, grain size, strain lines, etc , twin lines, distorted twins all show up....occasionally I use aqua regia at various dilutions for etching these, so the answer is yes! Useful information is obtained by etching electrum, most of my examples are unpublished or obscure, will tackle some publication of them in a year or so. Let me know how it goes. Don't forget that the gold alloys are very soft and easily distorted by cutting or polishing. Electropolishing is used sometimes to get over this, or etch/polish techniques. Sometimes etch-pits on the surface of the etched section have to be accepted as the best result if the grain boundaries and other features can be seen.
On Today 2:07 PM, [log in to unmask] wrote:
> Hi David,
> Is it possible to etch electrum and get any useful information? Would
> it almost always be solid solution... would that depend on the ratio
> of gold to silver?
> Do you know of any articles/results or photomicrographs or anyone who
> specializes in studying electrum? I'm doing some research on some Lydian
> electrum coins in the Harvard collection.