Silver PS3-5 large pendant with rhodolite garnet by Beverly Bartlett. 

Silver loop design, with texture on one side, rubover set with a pear shaped rhodolite garnet. 
On an 18" spiga link chain. 

PS 3-5 is based on the shape of a anticodon loop – which holds the ‘anticode’ for one amino acid at its base. This design, which has one side textured, is Bevley’s interpretation of this structure.