What countries use gold coins as currency?

Question

And is this an indication that they are a rich country?

Answer 1

None.  Gold Coins or any time of money that uses a Hard Asset doesn't work in a 21st Century Globalized world.

The problem is that the money supply is limited so it is inflexible. There is no central bank and if you run a trade deficit, you'll find yourself without any money because it will have all been exported.

There are pluses to Gold as Money, but only if you go back to the days of limited global trade to prevent your currency from escaping your economy.  For the most part, I believe the Swiss were the last to get off the gold standard back in the late 90s.