Vintage Silver & Turquoise Butterfly Brooch

Vintage, silver (tested, not marked) native American old pawn butterfly Such a sweet 🦋 with turquoise. No signature. There is an unknown "56" etched into back. I have several pieces in my personal collection and I am not familiar with this, it may have been a poor inventory practice for someone. I am unsure, this does not take away from the respect that this little beauty deserves. Patina untouched. 8grams From my collection, to yours 🙏