Why are gold prices so weird!

[Rob]

Hi,

I've just been pricing up some gold for a couple of rings and for exactly the same amount of gold these are the prices:

9ct white 164.70
18ct white 455.88
9ct yellow 161.61
18ct yellow 392.94

So here are my questions:

If 18ct gold contains twice as much pure gold as 9ct why is it so much more than twice the price and why is there such a huge difference between 18ct yellow and white but not between 9ct yellow and white?

Only asking because I know my customer is going to query the prices!

Thanks,

Rob.


edit I mean weird not wierd but I can't change the posts title!