I bought this at an estate sale so not sure of its history. After doing some research, I think the stone is black agate. The stone is about two inches long and an inch and quarter wide. We think it is vintage Navajo or Acoma Pueblo, or vintage Mexican, probably 1950’s or 60’s. Sturdy and gorgeous! A rare and beautiful statement piece. (I did the magnet test on it and it does not attract. So we think it’s silver) NOTE: The last photo is NOT my bracelet, but will give you an idea of the value. It’s really special! Lots of compliments every time I wore it!