Vintage Mexico large link bracelet with fire opal type Stones nickle silver 800

You are getting the vintage bracelet you see in the photo I am not familiar with the Maker's mark.I know that it's old Mexico.These are listed online as sterling silver, but I test everything so you don't get ripped off. and unless my tester went bad, I would say this is Nickle silver (German silver). I know those aren't called Opals , but forgot the name of the stones boxT