Silver Heart Locket w Etched Flower Design

I'm 99% sure this locket is sterling, but I couldn't find the mark. In excellent used condition, only the tiniest of scratches & none noticeable. The back still looks smooth and polished, hinges are in original alignment. Approx 1.25" x 1.25". Chain not included. Ships in new white gift box from smoke free home - ready for gifting!