TORTOISE SHELL EARLY PLASTIC VINTAGE CHOKER is probably from the 1940-1970 period. It could even be earlier as I cannot determine whether the tortoise shell element is genuine or not. My vote is that it is a sort of plastic. The length is 29 inches tip to tip and will be shorter of course when tied which is the type of closure it uses.
This piece is not marked and it appears to be quite old as it is made with black velvet laced in and out of the tortoise shell pieces. It is in good used vintage condition. Wear it or collect it, it has it all.