Vintage Delft Holland Sterling Signed Windmill Brooch Pin Porcelain

This pin test positive for Sterling, but it’s not marked. It is a porcelain, signed Delphi Holland pin. There is light some cracking in the glaze nut chipped just lines from the glaze cracking some. Beautiful piece it should be noted. It has a scalloped edge made of what seems to be sterling wire. The keeping in the back is complete, but it has lost some of its spring so to speak , so unless you have it to a scarf, it wants to come loose. The measurements are in the last few pictures.