Gold has the highest appeal among all assets and is universally accepted, making it the perfect asset to back a global common currency, which will definitely be a stablecoin in the near future.
However, a gram or a ton of Gold can never become a common currency; it should be something like a hundredth of a gram (0.01 g). Currently, a hundredth of a gram of gold is around $1.5, which puts it close to the dollar, the world's most popular currency.
Currently gold stablecoins are limited to a few unusable coins like XAUt ($4,557 today).