Is This Roman And Is It Gold

Peter..
The photos are quite blurred!..Could you upload pictures more in focus?...
Looks to be Roman maybe radiate obverse?
Trajan?..Severus Alexander?
What's the diameter?

I don't think it's gold. Otherwise, it wouldn't be corroded with all those deposits on the surface.

Uuuuuf!...
As a long shot Pete I'll go with a Trajan Dupondius.
Lets see what others come up with.
Agree with John on the base metal..
Looks to be a seated deity on the reverse.
Also pretty sure I can see SC in the exergue?
Paul..

..Good shout John.

I think it' another coin Paul just over about 2 cms

What's the dia. & weight?
It's Antoninus pius but looks odd?

The Britannia coin, I'm fairly sure is a modern replica. Being the first coin ever to depict and name "Britannia", it's a very popular coin in Britain - and so, one that is very often replicated and sold at ancient tourist-themed locations.

As for the squarish-shaped thing, I'm fairly certain it's not gold either - gold just doesn't turn black like that, not even in a fire (which is one property people have always admired about gold). Brass does turn black. But I'm not even entirely sure it's a coin. I don't see anything in that picture that's not explainable as random scratches.