'Iranian authorities, together with four local banks and Ghoghnoos, have launched the PayMon cryptocurrency backed by gold reserves, aiming to bypass international sanctions. No other country has ever used gold reserves to back a cryptocurrency.'
Note, there is the so called gold backed OneGram from the United Arab Emirates, but this is by no means an actual crypto.
https://coinmarketcap.com/currencies/paymon/
https://sputniknews.com/business/201902141072386638-cryptocurrency-iran-itcoin/