Unique Vintage Silver & Blue Stone Ring Size 6

Vintage modernist ring with markings - unfortunately I can’t read them. Appears to be a solid silver W Germany or Taxco made. I cannot be specific with respect to the stone, however, it is a very deep blue raw surface which can appear black dependent on lighting. Fits size 6 US. Nice solid weight silver preferable to the present day silver stamped 925. Rare - only one noted online. Genuine natural stone. There is medium wear to this ring.