I would agree identify a black beauty nickel can be very difficult.
My suggestion would be to acquire some books on
Jefferson nickels.
Some Jefferson books will a little information on black beauty nickel.
Learning the years that expert have found them will narrow your search.
I know I have Black beauty nickels from 1955, 1958 and 1959.
I do set them aside when I think I have found one. When one really jumps
out at me, then I know I have found one.
For the nickel posted ...it is a obvious environmental damaged coin.
For me .. sometimes I look at a coin and see what I want to to see.
Wanting to see something special. I try to set coins like that aside,
come back to it with a second look. The second look try to see the
negatives ...see what the coin really is.