UNO de 50 silver lariat necklace with faceted green stone

Signed UNO de 50 necklace in silver tone. I cannot find ant metal marks but I think this id silver plated. There is a pretty faceted green stone pendant on a ball chain with lariat style closure. There is ends can be pulled to adjust the length. Measures 44” at the longest. The pendant is is 1”. In excellent condition with slight tarnishing.