Salt. It shows up in our idioms about as often as our food. Even the word 'salary' is derived from salarium, the term for a Roman soldier’s earned ration of salt. But one of the most ridiculous lies perpetuated about this humble mineral is that in ye olden days, salt was more valuable than gold due to its function in food preservation. YouTube historian Lindybeige explains how this is all just a big misunderstanding.
According to trade documents from Venice in 1590, 33 gold ducats would buy you one tonne of salt. Similar figures exist from ancient Egypt showing that, no, salt was never worth more than gold. Duh. With the obvious stuff out of the way, there’s a reasonable explanation for the gold < salt notion.
The same Venetian trade documents reveal something interesting about the demand for salt: only one of those 33 ducats actually equated to the cost of the salt itself. The rest went towards transportation, tax, and profit. And people paid it gladly because salt was a necessity for survival. Those enormous mark-ups suggest that at one point in time the salt trade was probably more valuable than the gold industry.
So the next time someone says “salt used to be worth more than gold” you can pedantically explain to them that they’re partially right, but not for the incredibly stupid reason they’re suggesting.