Unique Triangular Onyx Vintage Mexican Ring Sterling Silver Size 6 1/2

Pretty and unusual shape on this vintage Mexican ring. Big triangular onyx cabochon set sideways. Nice. Different. Surrounded with delicate silverwork.
Unmarked as are many of the oldies. Tested Sterling.
The ring is size 5 1/2 and weighs 12 grams. Measures 1 1/2" wide. C 1970s
Inventory #JR 743