My VICTORINUS... this whole Era in Roman History is so messy... Coins, government, economy, barracks emperors... This is similar to @bcuda -man's RI Victorinus 269-270 CE BI Ant Gallic Empire PAX RI Victorinus 269-270 CE BI Ant Gallic Empire Salus
I don't think there's anything wrong with it. It was just struck on a flan with a higher silver content than usual. I wonder if it was overstruck on an older flan.
It looks like copper showing through on Victoria's chest and leg. If that is true, the coin was struck in copper, as usual. The silvering sure does not look like silverwash that was applied before the coin was struck, but it Looks like a silvering that was applied later (perhaps much later). If the coin is "pure" silver, i.e. silver or silvery metal through and through, then it might be a modern cast. I don't believe, that the coin was accidentially struck in good silver, not least because of the copper showing through. I would keep it as a curiosity. I shall post my silvered Quintillus Antoninian later on. The surfaces look quite similar to your coin.
If it was a $20 curiosity I would just keep it as you mentioned @Tejas but for me to have $60 tied up in it when I could have another coin with no questions does not sit well with me. I think I will return it , thanks for all the help everyone.
Here is my strange Quintillus Antoninian. In the beginning I thought is was a fake (modern cast). However, at the rim the silvering is broken in several places and copper is showing through, which makes me think that it is an original that was for some reason silvered, i.e. covered with a rather thick layer of silvering. I even wondered if this silvering could be removed, but I guess I just keep it as a curiosity. I was just thinking, could this kind of silvering by applied with some kind of electrolysis? Could it be removed in the same way?
I have one more curiosity of this type. This is a common Constans half-follis from Alexandria, only that the coin is struck in silver. The surfaces look entirely like that of a contemporary Siliqua. If anybody has an idea, I am more than interested.
There was a time when I was much younger that we threw pennies in well used photo fixer (containing a lot of silver from the images it had fixed). They came out silver color. We did it for the fun of it without intent of fooling anyone but I could see how a LRB could be stripped and plated to 'make it look better' using this method. These coins have been around for a long time and some have passed through many hands. 'Serious' collectors did not pay much attention to common LRB's even 30 years ago so they were available for use as playthings. I have no idea why your coin was plated but I can see a number of reasons that might be explained as, 'Because we can.' I will also point out that we rubbed the mercury from broken thermometers on coins to make them shine brightly. This was long before anyone (at least parents) knew that playing with mercury was hazardous and it was fun to push around a tabletop making little drops join into a larger one. Yes, it might be a miracle that anyone now over 70 survived childhood. I remember my father taking me out to watch low flying airplanes spraying crops. Everyone used DDT then but this was a decade before Rachel Carson published 'Silent Spring' suggesting that the pestacide might kill kids like me as well as crop pests. My father was not abusing his son; he was making him a normal boy in that time and place. Things like this make plating a few coins 'for fun' seem not so hard to understand.