This unique necklace is made by the War to Peace company in the USA. They recycle copper from disarmed nuclear weapon systems to create an trademarked alloy they call "Peace Bronze TM". This particular pendant is a aged Celtic Cross with a round intense blue Turquoise Center Stone that adds a Southwestern feel. 

Center Stone: 0.5" dia.
Pendant: 2.75" x 1.5"
Chain only: 9"

This really is a beautiful piece.

Thanks for looking.