Cuda 70 that is one nice artifact. 3 guesses: 1) brooch; 2) pendant that once held a cameo or picture; 2) horse bridal rosette (although I've never seen one like it). Consider posting clear pictures with a size reference. Also mention if there is any lettering on the reverse and what, if anything, you found nearby.
I took the liberty of trying to enlarge and enhance your picture to make it easier to view. Can you give us a size on it? A picture with a coin next to it would help.
Size about a 1” in diameter. No lettering. Also found some old medicine bottles and some dish/ plates pieces. Got to get the glue out. Thanks for you assisting it what this might be
The button may date a little later in the 1800s and may have had a glass insert. I wish I could be more specific but I haven't found anything to compare it to yet. The design of the border says Victorian era to me.