Here is a rather chunky unusual ring, with a large black round stone (which I believe to be a black Onyx) claw set into a high mount with openwork decoration to the mount and shoulders.

It is stamped 925 inside the shank.  

It has an old resize on the back.

It is a UK size M. 

The black stone measures approx 16mm in diameter.

In good condition with some general scuffs to silver.