This sterling silver ring dates from the 1920's or 1930's when marcasite jewelry was worn as costume jewelry, imitating the look of the higher-priced gold and platinum jewelry of the age. This ring has an octagonal shape with a pretty blue jasper cabochon prong-set into a rectangular cartouche. The back of the ring has decorative Art Deco style engraving; this was not done on reproductions. The ring is marked "sterling" inside the band. The top of the ring measures 1" X 11/16" wide and is a size 5 1/2. It weighs 6..1 grams. It is in excellent original condition.