Gold Filled Shell Cameo Brooch Heart Filigree Setting

Hand carved shell cameo set in a lacy filigree setting with a heart design. Setting is a brooch. 1/20 12k gold filled and marked as such. 

Pin back has locking clasp. Measures 1 1/2" tall by 1 1/4" wide. Weight: 7 grams. Need light cleaning. Nice condition. C. 1940-1960.