I Just Bought A Tiffany & Co Necklace And Bracelet Set For $220 On Ebay. How Can I Tell If It Is Fake Or Real?

It looks legit but then I read somewhere that if it is shiny that it means its fake? I have run my nails along all the links to check and it is stamped with Tiffany & Co and also 925. I just want some help as I am giving the bracelet to a girlfriend for her birthday and I’m trying to log into the Tiffany website at the moment but I can’t so HHEELLPP!!!