Answer:
No longer used.
Explanation:
Due to too much paper money being printed, some countries did not have enough gold reserves to exchange for the excessive amounts of paper promissory notes. (China's overprinting of printed money during the 9th and 15th centuries foreshadowed England's overprinting during WWI some 200 years later.) This rendered the paper money worthless. (One of the causes of the Great Depression.)
The gold standard is no longer used now, but the system it inspired is currently used between nations.