I'd guess it's a piece off a necklace or bracelet? Definitely looks old. I'd hit the area where it was found in case something came apart and left other pieces. It's a piece of treasure for sure, and a keeper. Well done & congrats!
The first thing I am noticing is the zig-zaggy etchings present. I have founds a lot of early trade silver here (Northern Michigan) and it seems like those zig-zag markings were commonly added as a design by the silversmiths (might have just been a common design technique to make it more flashy possibly).