These are probably Sterling that has a very small amount of 18k gold on the front. A lot of the time the gold is so thin foil that its not worth more then the silver. Just guessing there is probably more silver scrap in it then what you paid for it.
From the pic it looks like one side is gold and one side is silver... However I don't know the makers mark but the markings are legit.. I'd say its real gold and silver for sure though.
It could be a John Hardy piece. I found a neckless of his made of ster. & 18K years ago and paid 17 bucks for it and it went to Australia for around $455 I think it was. If it is a JH piece in Ster.+ 18K , you got a gem and a well sought after piece. I believe the JH marks have changed from the early pieces. If not JH you still have a gem I think would at least sell for close to $200. The Official John Hardy Online Boutique - Designer Handmade Jewelry