I came across this piece about 5 inches down and it looks like it was brass or at least plated, there's a couple of small scratches and they're shiny. The quarter is there just as a size reference.
I'm very surprised that it's still intact. Any ideas?
Spring tension finial... maybe. It would be held down by spring tension much like old hood ornaments. Or, maybe it's a cabinet turn knob that hooked to latch. I don't know, just guessing.