VINTAGE/ANTIQUE Brooch, few stones missing, well worn but pin works 3" x 1.5"

I dont know exact age but it was my Great Grandmothers and I am 77 y.o. She passed in 1977 at 87 y.o. so I would venture to guess this must be 70 or 80 years old. a few stones are missing and lovingly worn. but pin back is still in good condition. this looks brassy or bronze ??? This is a very unique design and would be a good find for vintage lovers