Unique, One-of-a-kind Vintage 1950/1960s Cannetille Hidden Pen Necklace.  Pen Measures 3", chain is 20" in length.  The pen has no ink and cannot say if it would then actually write if it did.  
Cannetille: A cousin to filigree, cannetille consists of fine, twisted metal wires coiled in patterns to create three-dimensional designs.