I’m sure I’m not the only one who’s noticed it. As I’ve become more interested in the coinage of Alexandria, with its interesting and sometimes bizarre imagery, not to mention the lovely feeling of a chunky drachm in your hand, I’ve also noticed that its issues seem unusually predisposed to bronze disease. Take for example this latest coin I acquired, which I am still in the process of treating. Thankfully the corrosion only covered the surface for the most part, but it arrived in a flip that was accumulating green powder at the bottom, and it left a powdery residue on my hands from just handling it. It actually added a nice highlight to the devices, but for its own good it is now soaking in distilled water due to its flakiness. Then there’s this, a product of the minting process at Alexandria, which has resulted in what appears to be a bronze disease sandwich. Thankfully it seems stable, but I don’t know how to treat it. There’s no way to clean it out, and for all I know it has a core of solid bronze disease. I even see coins that look diseased being offered at major auction houses, with no mention of the problem. Why is it that these coins which were mostly likely found in the same dry environment in which they were made are so predisposed to bronze disease?
Not that tetradrachms from Alexandrian don't get their fair share of BD, but the drachms and lesser bronzes nearly always seem to have BD. Partly why I ignore them.
An interesting question - maybe they were buried in the Nile Delta, a somewhat muddy/swampy environment, and the home of most of the Greeks in Egypt, along with Alexandria. One would expect the drier parts of the Nile Valley, from Cairo south to Aswan (about 800 miles) would produce less bronze disease. Anyway just my theoretical $.02.
I have always wondered if many were batch treated improperly when found. I know many of what we had were once owned by a few major collectors. Did one of them bathe coins in HCL?
Cool questions... made me go look... I have this AE from Egypt that has cool highliting like your BD (thank goodness, mine is not). RI Agrippina II 50-59 BCE AE 26mm Egypt Bust of Euthenia w Corn in Hair RPC 5188 But, then again, the background... >shudder< ...is the Seller's pic. I have not photo'd yet.
I think that might be part of the problem (not really in HCl, of course, but something unwise nonetheless, plus improper storage). @ancient coin hunter might be on the right track too. I haven't counted but between potin tets and drachms/hemdrachms/obols/other bronzes, it seems evenly split or more prevalent among tets. There's no denying it's a problem, so collectors of Roman Egyptian coins have to be prepared to deal with it.
Thank you for posting this, @SeptimusT, I gave your post a like not because I'm happy about the bronze disease infection in your Alexandrians but because it reminds us to be vigilant in our inspections of our bronze coins.
Thought I'd share an update on the title coin. Appreciate everyone's comments, as always. This is the result after around a week soaking in distilled water, with some scrubbing from a toothbrush and a little bit of poking and prodding around in the cracks.
At this point, I would set it aside and examine every day for return of the light green material. I would expect it within a week but could cut back to more occasional exam if it is clean after a month. If it shows zero regrowth/reinfection, there is no reason to do chemotherapy. When it does, you have little recourse. What you do not want to do is stop checking the coin.
