1960s Jet Choker Necklace w/Solid Brass Clasp- 939 $50 or $45 w/offer

This 1960s jet choker with solid brass clasp is a true classic. The stone is authentic as it is solid, cold to the touch and heavy. The stone I am 90% sure is jet as it was often used in jewelry back in the 1960s. However, it might be onyx. The necklace has 5 beaded cords. The clasp is none magnetic so I safely assume it is solid brass. It is a choker length.