Jon, I don't know. But.. I think it is some type of latch for cloth. At the top , the brass is split down to a point. I think a very thin leather or cloth was slid down in the split , crimped back and pinned . I believe it is CW period or slightly earlier and I don't think it was in use long after the war .I dig a ton of 1890-1900 house places and you won't find one. I have enclose a picture of the ones I have found over the years , all were found on period or early sites. They come in slightly different sizes. Please post it , if you find the answer , I would like to know also. Good luck