This is a fantastic and rare carved carnelian ring marked "Germany Sterling".  The carnelian stone is carved in a puffy shrimp-like shape and rises high above the setting 3/8" (10mm) and measures 3/4" (17mm) long.  It is hugged in place by two double prongs on top and bottom, and two elaborately decorated silver fan-like prongs decorated with marcasites that graduate in size.  This ring is from the 1930s with grand Art Deco styling and is a size 5 1/2.

Front view:

Side view: