I believe these are either Lucite or Celluloid. The beads on one of the necklaces are oval in shaped and an opaque, butterscotch-orange amber-colored with dark brown and yellow marbling. I think this necklace may date from the 1940s but it could be thru the 1960s.
Most things are from my own collection. I’m not an expert. I do not always get to clean the jewelry, although I try. Also, I use a 15″ necklace display, so that gives you an idea about size. I love looking for unique pieces, it’s fun to wear, doesn’t have to cost a lot and it doesn’t take up a lot of room!