Huntindog is on the right track. Could also be half of a brooch. That rectangular part at the bottom of both pictures is where the other half would attach (I think). Looks 19th c.
For any readers here who don't already know it, here's a relic time-dating tip. If the object is American-made and has a marking saying "Pat" or "Patent(ed)" followed by a number rather than a date, it is no older than the early-1900s. For US-patented objects, the change from using a date to a Patent number happened sometime in the 1920s, if I recall correctly. Somebody here might know the exact year, but my now very elderly brain has forgotten it.