Silver Necklace with Half Inch Starfish Pendant

Cute necklace with a small pendant featuring a starfish on a sky blue/turquoise backdrop. Perfect for a girl, teen, or woman! The chain and side/back of the pendant look like oxidized silver and the extender is more traditional silver, but I don't know what the material actually is. The pendant measures ~1/2" long. The chain is about 16" long with a 2" extender. Closed with a right-handed lobster clasp.