Damn, round ice cubes. I have been living in the dark ages. I tend to drink my whiskey neat. I might just try a round one cube someday.
Can't believe it took so long to figure out with all those clues. Certainly doesn't look like any ice cube maker I've ever seen.
Very close! However in the full image it does not appear to be used as a broach. To be honest, I'm not sure myself, but given it's size and possibly weight, it might be awkward to wear. It is man made, but I don't know the materials used. You know what? I looked closer and I just noticed the pins, so it is a broach! @gentlesenior wins!