Nokta FoRs Gold, a Gold Cube, 2 Keene Sluices and Lord only knows how many pans....not to mention a load of other gear my wife still doesn't know about!
depending upon its size --it might be part of a suspender clip -- or a box top clasp -- the pin part was to allow for movement ..so clearly it moved some how , for some reason ..... it might be part of a book hasp /closure ...