Sterling Silver Onyx Marcasite Ring

Here is a fabulous sterling silver ring featuring an oval black Onyx with marcasite around the Halo. It looks to me like there are some pieces of gold on the Halo as well at each tip. There is a Hallmark stamp on the inside band but I cannot read it. It is also marked 925. This is a knuckle to knuckle ring and would make a fabulous statement piece!