This is a nice translucent blue high quality Chrysocolla (Gem silica) set in an Art Nouveau Wave Ring design.
Gem Silica is the highest quality form of chrysocolla. The predominant silica or quartz is permeated with minute crystals of chrysocolla showing a beautiful blue or green translucency through the stone.
The stone is a hand cut free form and measures 10 by 7 mm or 3/8 by 1/4 inches.
This ring is a size 5 1/2 but can be sized up to a 7.