Sterling silver minimalist poison ring with large Oval robin egg blue turquoise stone it has hidden compartment poison ring or locket ring marked 925 on inside it is real turquoise the black spots are remnants of the host rock measured the inside diameter at 11/16th an inch or 17.46 mm -- which i believe is in between a 7 & 7.5 based on online conversion charts the stone itself is approximately half an inch by .375 inches