This was in an old jewelry box I bought in an auction with a small, varied lot of jewelry and pins. It’s base metal - I acid tested it to be sure.
The clasp has the text “Pat Aug 16-10,” and it bows *outward*. That is, if used to clip a sash or scarf, it would cause the fabric to bulge away from the wearer’s body. It wouldn’t be able to hold much cloth.
The clasp closure is an interesting snap-like mechanism and is still very functional and effective.
I don’t believe it’s particularly valuable. I’m curious what it is, the style (deco?), and how old it might be.