Vintage Mother of Pearl Belt Buckle (?) for Scarf

I believe this is a mother of pearl shell. Loops on the back to thread a scarf/fabric through to make a belt. There is a tiny chip on the edge. Please see photos. This is vintage. Was my mothers, and possibly from the 70s or 80s. This is beautifully polished and shows iridescent colors of blue pink and green on a silvery white tan brownish background.