great looking piece of cutting - nice find. I'd suggest the finer cutting is mostly strawberry diamonds. Unfortunately, like so much unsigned cut material, it may remain without attribution, and about the only thing of use I can think of suggesting is the possibility of The American Brilliant period (ABP) - of which we get very little on here, but it might be worth pursuing. Also possibly an Irish origin. I'm not suggesting it is either of these, but might be food for thought.
Presumably it was made as a decorative piece only - can't imagine it would be for actual use. Can't really see the extent of wear - does it ring well if flicked? Think I would have brought it home too - sorry this not of any real help.