Sterling Silver. Very pretty faceted Tanzanite in a purple/blue hue.  The rustic shank was made by heating the surface of the silver and carving into it with a stylus (PLEASE SEE THE VIDEO THAT GIVES A SENSE OF THE SCALE) It measures 1/2" long (down the finger) and is a size 7-3/4. I am sorry IT IS NOT sizable.   EXCHANGES ACCEPTED WITHIN 10 DAYS FROM RECEIPT.