So I came across this coin (not interested purchasing just really curious) and I am really troubled with how the oxidation of it formed. The only time I can think of coming across a similar looking type of oxidation is on british museum Mithridates VI coin on a photo from internet, you can see it on the ridges of his hear. So why is it so dark and so clean in the same time. Is it a toning that developed after it was cleaned? Was it developed and badly cleaned? Or is it horn silver that was cleaned only in parts? I am really curious. Thank you all!
The owl tetradrachm was part of a bigger group which remained unsold for several auctions of a German auctioneer in 2015. Having seen the others, I would rather say someone overcleaned these coins and then attempted to apply some kind of fake toning. Edit: I just checked out of curiosity and it seems they are still trying to sell it. I didn't count but it must have been listed in at least 20 auctions of the same dealer in the past 6 years.
I believe I paid too much attention to the second photo and just glanced at the first. I completely agree the Athenian tet looks colored, for reasons I do not know Looks like black paint. The second to me still looks like horn silver in the recesses, but you are right the Athenian piece is not natural at all.
The Athens tetradrachm looks like an attempted cleaning job. The coin probably came out of a hoard, very dark, and someone tried to remove the hoard patina. The metal in the cleaned areas does not seem crystallized, so with time, it will darken somewhat.
