Gold alone does not make a stable coin. There is a absolute necessity to have it balanced with silver-coin. Else, all you will see is high inflation, as Spain in the 15/16/17 century can attest to.

Coin' s financial school.pdf Read it. It explains this process of counter balancing perfectly.

In today' s world we can see this same process in fiat. Albania for instance, uses it' s own currency and the Euro to balance things out. In Switzerland the WIR is the counter balance to the Franc. It does not mean it is stagnant and frozen but it hoovers around in a bandwidth against each-other.

This system of balancing and hoovering was used to make the EMS as a preparation on the Euro introduction.

Once you can comprehend this system, and the wisdom it entails, it is easy to see why first the Silver was taken out as a means for payment.