Wow, you dug up another of the bumpy black beads in place on the same sort of box chain necklace! I continue to be puzzled as to why the silver (?) was applied to the outside - maybe so it wouldn't look like a tiny Christmas tree ornament?

Following your clue about Miriam Haskell, I found a couple of images of necklaces attributed to her, either sold or currently for sale on Etsy. I see what you mean about that turquoise chip bead.

Which necklaces might be originals and which could be knock-offs - and who did the knock-offs of whom [remember that Camel's Bell shop in Peking, that also had boutiques on cruise ships?] - does seem like a nice question.