Sterling Silver. This is a pretty soft pink tablet cut tourmaline with natural internal inclusions that give this stone so much interest!  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 5/8" 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.