EUC Vintage art glass necklace

artesian glass necklace. my mom is downsizing and I am selling some things from her collection. this is beautiful statement necklace. the clasp needs cleaning - stamped 925. **updated last 2 photos: I polished the clasp with a cloth and you can see the shine coming back. if you have a solution (or a lot of patience) even the black tarnish spots will come off... approximately 17.5"