Beautiful, Blue/Turquoise, Crystal Rhinestone Dragonfly Pendant Necklace  by Betsey Johnson
Drop of Pendant: 2.75inches/ 6.6cms
Width of Pendant: 3.25inches/8.5cms
Length of Chain: 24inches/61cms + extension chain
 
Betsey Johnson is an American designer best known for her feminine and whimsicall designs (from Wikipedia)