Gold has been used as money for many reasons. It is fungible, with a low spread between the prices to buy and sell.
Gold is also easily transportable, as it has a high value to weight ratio, compared to other commodities, such as silver. Gold can be divided into smaller units, without destroying its metal value; it can also be melted into ingots, and re-coined. The density of gold is higher than most other metals, making it difficult to pass counterfeits. Additionally, gold is extremely uncreative, hence it does not tarnish or corrode over time.