What does the back look like (any marks at all?)
It’s different enough from a Florian cross that I don’t think it’s firefighter related, but I can always be wrong.
Looks to me like a faceplate for a lock; they key would have been round, with two 'toothed' edges. Just MHO. Any indication on the back of a way it could have been attached?
It looks the same on both sides no markings no way I could see it being attached. Starting to think this was something someone repurposed since the edges are sharp and its not uniform, one edge is longer than the others
While it does have the general shape of the firefighter's Maltese cross, it isn't like any other FF cross I've seen. I'm more inclined to agree with the the folks above thinking it is some sort of locking mechanism face plate.