Antique chandelier

It's a underwriters, something or other, inc. R with circle around it. Listed electric fixture issue no. C-273,733. E-33879 chandelier. It's really dirty and needs cleaning but I have figured out that it is not good to clean what u know nothing about. I can't tell what it is made of. It looks almost tarnished in places and blackish in others. It looks like it could of been silver at some point. Maybe brass not too sure. But it is extremely heavy I mean heavy. It don't have any of the crystals that it once did and the bottom of fixture is missing I guess. It's almost a green color tarnished in some places. Just would really like to know what I have here if anything at all. I'm not sure if it works I got it just like it is now I haven't done nothing with it. Let me know thanks for your time. Oh yeah my son tripped over it even though it was out of the way in my bedroom and I didn't think nothing of it until trying to take pictures just now and realized one of the curly hooks at top had broken off I found it over by dresser I hate it to pieces but when looking at the inside of broken piece it is silver I will take close up pictures to show u maybe u will be able to see even though it probably ain't worth nothing especially now it's broken I'd like to know about it.