Yep, got it. So it is gold. I guess it is just gold and copper and it got the colour from the copper within.
I just never seen such reddish gold (not that it means anything).
PS: I like this colour much more that that of pure gold.
I don't know by which reason it's like this but I know for example that gold from Bali look different than gold from Java, Javanes gold is more yellow and Bali gold has a reddish colour.