o.k., I'll give it up: bill actually posted the basic shader in his floor-tile thread.  it's  ... oh, fab, I can't even find it now.  the one with the blue tiles and the procedural with the schlick approximation inside a red rectangle.  all one really needs is to take a few fotos of some gold items, preferably as large, as flat and as solid gold as poss.

p.s. the coloured reflections may look fake, but I tried it with some flat gold surfaces and it really does reflect most colours quite well.