Hadrian Denarius With Verdigris?

I just got this denarius in, so I haven't made an official attribution or even have the size or weight measurements yet, but I'd like to get some opinions of what appears to be verdigris on the reverse:

To my knowledge, there should not be any verdigris on a silver coin, since verdigris, I think, is a result of copper reacting to oxygen. Am I correct about this?
So do you think there is an unusually high percentage of copper mixed in with the silver of this coin, or is the verdigris just contamination from prolonged contact with a copper coin?

Here's a close up of the reverse:

It looks like someone tried to physically remove some of it down near the base of the figure and then give up because of the scratches he/she was making.

Do you think Verdicare might help remove it?

 

Log in or Sign up to hide this ad.

My Nerva tet also has some Verdigris on the reverse, a tiny patch. The dealer I bought it from only had a black and white photo so it was not visible until the coin was in hand. Kind of a bummer and I paid $135 for the coin. The silver content of the tets by 96 A.D. had dropped, so I guess this might have been expected.

 

It looks like surface deposits to me-- copper-bearing surface deposits which have developed verdigris. A few short soaks in lemon juice will probably take them off without harming the coin, if you are considering cleaning it.

 

It looks hard and shiny like bronze patina, and assume that the coin spent a lot of time in the ground alongside getting cozy with an AE coin that developed the patina. I wouldn't think Verdicare would do anything to it. And as the scratches suggest, it is probably very attached and manual cleaning would make things worse.

 

Logical answer is floree.

 

that likely came from other bronze coins it was buried with over the millennia..

 

Perhaps you are thinking of fourree? https://en.wikipedia.org/wiki/Fourrée

 

@gsimonel, I'm curious if you had tried anything on your coin or if you just left it as - is?

 

I tried soaking the coin in lemon juice, but that didn't have much impact, so I got a brass rod that I filed into a point and looked at the coin under a stereo microscope while carefully scraping away the encrustation. When I got close to the silver I'd take the coin out from under the scope, rub lemon juice on a new area with a Q-tip to get the remaining traces off, then go back under the scope to work on a new area. After switching back and forth from scope to Q-tip for a few hours, I got this result:

Thanks to everyone for the advice.

 

Nice job. Patience is the key when doing this type of cleaning.