How can you tell if something is real silver
Signs of tarnishing, real silver also has a distinct smell (hard to explain) manufacturers markings. You could also have the piece tested.
Take it to a silver retailer.
Sliver sometimes has the letters ag on the back which stands for silver.
Often you 925 is inscribed on the inside of a piece.
do all of the above, but first check if it's magnetic, if it's not, it could be silver :)
Silver turns black in salt water