AB rhinestones date the set to 1955 or later. Screwbacks make it most likely no later than 60s; I'm not sure when screwbacks finally went away. It's possible - maybe likely - that only the earring backs are sterling; you see that sometimes in older earrings. I'm on my phone and don't have my bookmarks; Sandy's dangles page (link is in the Resources thread) should have that teardrop dangle. I think it was one that was used by several companies. My first suspects would be Lisner and Star, if indeed it can be attributed and wasn't the work of an anonymous jobber.
