A&Z Hayward I Blue Stone Cabochon 14K GF Necklace

A pretty A&Z necklace w/a striking gold-filled pendant & a blue cabochon stone at its center. Unfortunately, I don't know what type of stone it is! It's opaque & obviously blue. Lapis lazuli? Sodalite? Photos 5-7 show hallmarks/stamps, "A&Z", "1/10 14 KT GF" & the clasp is imprinted W.E.H. for Walter E. Hayward (merged w/A&Z in the 1970s). Measurements in photos 8-10. Dates anywhere from 1970s-2000, when both A&Z & WEH TMs expired. Best guesses! Comes in old Hayward Supreme box, last 2 photos.