10K Diamond Birks Burkhardt Yellow Gold Square Tie Tack Lapel Pin 7x7mm

Vtg 10k Diamond Burkhardt Birks Yellow Gold Square Tie Tack Lapel Pin 7mm x 7mm Vintage Burkhardt for Birks 10k yellow gold tie tack / lapel pin w Diamond. Classy accent piece perfect for formal black tie events / weddings . I’m unsure if back piece is gold or gold plated but pin itself is stamped with a B in a hexagon & 10k. Diamond has been tested & confirmed. Measures 7mm x 7mm