VTG Onyx & Marcasite Sterling Silver mourning Collar Brooch Pin 925 silver

The Onyx & Marcasite Collar Pin is a mourning brooch in sterling silver set with a single piece of stunning onyx and two dozen tiny marcasite chips. All of the marcasite chips are accounted for. The only thing I see as an issue is there is a very slight bend in the pin rod. I tried to show it in pictures. The brooch measures just over 2.75 inches across, a perfect example of the style.