Well gold has nothing to do with economics, so that's irrelevant.
Except gold has been long accepted as a means of exchange - dating back centuries. It still has intrinsic value beyond just being shiny and pretty for jewelry.
Thus it has a lot to do with economics. Read up on Executive Order 6102.
They outlawed possession of gold gave people 20.67 per oz. for the gold they turned in. 382.00 in today's money. This was not a fair price. Then they raised the price of gold for international exchange to $35.00 (648.00 per troy oz). Violations punishable by fines that would be worth 150,000 in today's dollars.
The only reason gold is valued is because it's shiny and pretty. It doesn't have some magical value that paper money doesn't.
It is not about being shiny. People have been using barter & exchange for long including food articles as medium but needed 1 unit of exchange before fiat money came in.
There are certain basic requirements for that - Durability (It can't be perishable like food articles), divisibility - You can pile up coins or weights of gold & standardize units (How do you divide food articles & many other stuff), Low Weight (You have to pile hugs stocks of food articles or other stuff).
There are many reasons why metals were chosen - Gold for example has limited availability, stable production across time (no huge short supply in winter), has high replacement cost, is non-perishable, durable, divisible, portable (easy to carry etc) ! Pretty basic economics when studying the monetary system !
