Australian Chrysophase stone cut and polished square, mounted in a hand engraved textured sterling silver setting with an adjustable silver ring shank.  Hallmarked at the Goldsmiths Assay Office in London.  The Chrysophase was mined in Australia in the 1970s and I recently acquired these stones from a gem dealer and hand polished and shaped each stone to size for the ring.  The ring size is currently size O but I case easily adjust it to suit your size if you just let me know your finger size.
Top of the ring measures 30.4mm x 31.5mm.
The depth of the stone and its silver bezel is 6.4mm.
The overall height of the ring is 27mm.