Gold Price Chart -USD
The price of Gold (AU) is universally followed in financial markets. For hundreds of years, Gold was the foundation of economic capitalism. This was before the repeal of the Gold standard, which caused an extension of the fiat currency system. As a result, cash doesn't have a direct tangible backing form of monetization.
On the periodic table of elements, AU is the code for Gold. It is quoted in US currency and it is how the value of Gold is measured across the globe.