Gold is used as investment and purchased in a shape of coins or bullions, it is mostly used by Global Banks as reserve asset. In times of crisis, such as inflation or economic crisis, gold is seen as a stable investment.
The intrinsic value of gold is determined by its relative rarity and the average applied work performance in his promotion. That's because gold has no counterparty risk, as other systems of paper currency in which the interest rate after the perceived risk of insolvency depends on market participants.