The color of this necklace will astound you!  It's a beautiful Caribbean blue; I'm not sure what kind of stone it is, or if it is glass - but I do know it is gorgeous.  The double-chain necklace measures 18" with the center drop measuring 1 1/2".  The round glass pieces measure just over 1/2" across and are bezel set into a very thin metal, possibly tin?  Each stone is linked by double jump rings.  There is no clasp, but a hook (it operates).  The overall condition of this very eye-catching piece is very good.