The listing, Sterling Silver Large Glass/Crystal Pendant has ended.
Not sure what it is except that the pendant is sterling. It almost looks homemade from an old smokey lamp crystal. But to be on the safe side I am going to say its glass, and if its better then that its better for you. This was found on the beach while metal Detecting a few years ago, I polished it up with a silver cloth then, put an ad up on craigslist in the lost and found and no one claimed it. So now it can maybe go to someone who will wear it or maybe use it for something else.