It looks genuine. As with Bob L's link, it's a Probus antoninianus from Rome, minted AD276-282. The reverse is ROMAE AETER. The reference is RIC V Probus 187 http://numismatics.org/ocre/id/ric.5.pro.187
Quite a few mintmarks are listed (probably to identify each 'officina' at the mint). I think yours is RVA, a few of which you can see on the link above.
It's 'silver', but official coins by then were somewhat debased so it contains a lot more copper than earlier Roman coins. It might even only be 5% silver.
Despite being very old, it's not worth a huge amount, especially as it isn't in pristine condition.