This item is 2 inches long. The shaft is magnetic, but no rust, so must be high carbon. The bulb at the top appears to be brass, with a knurled edge. I suspect a part of a tool, but it is not threaded to screw into anything.
Yup, looks like an awl of some sort, I would have expected it to be threaded if it was to be part of a square.
Videos I have looked at say this is the first part of a square to be lost, and this one is certainly a good example of one that would disappear quickly!