Gold can be traded on the stock market as a commodity, and in fact more than 930 tonnes of gold are cleared through London every day. However, this is virtual gold which is bought and sold. No actual metal changes hands. The stock market price is artificially much higher than the actual value of the metal. This is not a good basis for any currency. This was brought home to the governments of the world in 1968 when gold was allowed to float freely rather than being fixed in price. At first the value rose, so that by 1980 it had reached a record high of US$850 per troy ounce. Then the price started to fall and by 1999 was down to less than a third of that. Now governments no longer use gold as the standard and are selling off their gold reserves.
This is both a lie and the truth.
Actually, they are both lies.