https://www.vcoins.com/en/stores/ma..._kings_menander_ar_drachm/866401/Default.aspx It looks like someone has coated the coin with something to make its design features easier to interpret--but I feel it goes much too far. Or am I going much too far?
I named it "Selective Corrosion" when I first saw it on an 18-something Bust dime in the '70s. However, on your coin it is too wide spread so it is just corroded. If the smooth surface on the bust is actually wax, then someone did an unbelievable job so I'll agree with the poster above.
Hello @Nathan B. I agree with @Herodotus , that it looks like some of the original surface and tone have become delaminated. Meaning that, some of the original surface, which has a nice tone, has fallen off, exposing the underlying, granular material. The underlying material is granular, perhaps because the original material was a mixture of silver and copper, and the copper may have gradually dissolved/leached away, over the past thousands of years. The leaching of the copper, may have weakened the material, leading to some of the original surface falling off (delamination). I'm no expert. This is just my best guess or theory. There are CoinTalkers, who know way more about this sort of thing, than I do. Hopefully, they will correct me, if I'm incorrect.
I don’t think ren wax would be able to be that thick. Every time I’ve used it it’s been rather thin and just barely fills in minor surface flaws
To clarify, what I meant to say was, I was agreeing, with what @Herodotus said, about the delamination. I neither agree nor disagree, with what @Herodotus said, about the Ren-Wax. Maybe the coin has Ren-Wax, and maybe it doesn't. Some of the coin's surfaces are nice and smooth, for example in the center of the obverse, and the letters from 9 o'clock to 10 o'clock on the obverse. Those are the surfaces that haven't delaminated, I think. Some of the coin's surfaces are rough and grainy, for example most of the areas near the edges of the obverse. Those are the surfaces that have delaminated, I think.
My thanks to each of you, Herodotus, Insider, hotweelsearl, and sand for your comments! When I saw a picture of this coin for the first time, I thought: is the surface peeling off, or as the coin been coated with something selectively? I ended out deciding that the surface must have been coated selectively. I agree with Herodotus and Sand who have taught me the term "surface delamination." I still think the coin looks coated in something, though. Perhaps it's a bit of both. There is some delamination occurring on the coin, but perhaps there is also a coating of something, too.
As a follow-up to my strong opinion against Ren Wax: Here's my most extreme before an after with the Ren Wax. As you can see, in no area did the Ren Wax add any significant layer of anything to the coin. It filled in very minor surface flaws and pits, but the stuff simply is not dense enough to be able to be built up in any significant amount. Even if it was dense enough to be built up, it would be like candle-wax, and easily removed with a fingernail or toothpick. There's the possibility of a rather more sturdy and hard substance, maybe paraffin wax or a type of varnish, but I highly doubt it's any temporary substance; any temporary substance would be easily removed via soft, mechanical means. The test would be thus: use your fingernail and attempt to pick at the edges of the "lamination." It if flakes off easily, it's some sort of wax or varnish. If it does not, then it's more likely a break in the patina, some horn silver, or another metallic situation. For example of a patina break, I have this Hadrian which once had a smooth, glossy dark green patina. This patina was broken by what I assume is a failed attempt at electrolysis. This is somewhat similar to yours, as it looks like there is an artificial substance deposited on top of the coin. However, it wholly solid, and no amount of mechanical forces, short of grinding it down, would be able to remove thet top layer.
Original patina has come off on edges. Not an unusual phenomenon. Nothing to do with Renwax or electrolysis. Patina, which is sometimes like the coating on a peanut m&m can chip off, corrode off, or just wear off in spots. The part you don't like is natural, even desirable. Lots of different types and thicknesses of patinas. Care must be taken to preserve what is left as it is protecting what's underneath it. Don't try to take it off. You are going too far if you do!
