What is this gold stuff?  https://s-media-cache-ak0.pinimg.com/236x/a7/42/52/a742522fb21957e96f1fa97fb6958e33.jpg

My guess is gold leaf...which would make it very expensive.

You can also spray a cake with gold paint...the gold will be deeper if your fondant is already coloured in yellow.

Yes, as MKC said it is definately gold leaf.  Gorgeous technique, tricky to master.  This cake has been done by someone who has had lots of practice, and works in a room with zero air movement.

Thanks!