leopard mark or a cat mark

small eyeglasses that fold up and flip open with a lever on the side. The small dainty handle measures two and half inches. Inside the rim that rests on the bridge (when open) of your nose there is the small mark, not flat but incised, if that is the correct term. Probably turn of century or late 19th? The handle ends in triangular opening that could be hung from a chain. It all looks to be gold, but it only has that one mark which curves down on the top. Can you enlighten me? What web page will answer appear?