This is a modernist brooch or pin made by G.N. Buonanno of New York.  The piece is made of gold toned metal in a curved rectangular form.  It is studded with semi-precious stones - a large coral colored stone, two small purple stones and three black ones.  It measures 2 3/8” in width by 1 1/4” in height across its widest.  It is in very good condition. 

This is a wonderful brooch, very modern design!