Carolyn Pollack Sterling Silver Choker Necklace with Black Agate Pendant Enhancer Genuine Black Agate and .925 Sterling Silver Necklace is Adjustable 16" to 20" L, Pendant Measures 1-1/2" L x 1-1/8" W See Ruler View for accurate sizing. Silver may tarnish over time. Handcrafted in America with lifetime warranty on all jewelry Adjustable sterling silver necklace in a graceful rope and scroll with the black agate pendant.