There are 158,000 tonnes of mined gold in the world and, it is estimated, another 100,000 tonnes of unmined gold. At current rates, the supply is expected to last 45 years.
Pure gold is non-toxic and is sometimes used as a food decoration in the form of gold leaf. In medieval Europe it was used on food either to demonstrate a host's wealth or in the belief that something so valuable must have health benefits.
