None of the money is natural, even gold has to be coined into unique form and weight to circulate as money. People usually do not accept gold bars/nuggets because they can not tell the purity without professional equipment. Then the trust falls on the quality of those gold coins and the issuance of those coins, so they are usually made by authorities (gold smith centuries ago then later coinage organization). That's the key to money's value: An authority that people can trust
Using gold as money is an effect not a cause of gold's appeal to people. Bitcoin, like other fiat monies, doesn't have this attractiveness through its own existence per se, i.e. beyond the function of being money. In fact, its very existence is a result of conscious effort...
That was my point (natural vs artificial)
Gold is also an attempt to abstract value. During early Egypt time, gold was only used for decoration, the money at that time was grain. The move from grain to gold is one step further in the process of abstracting value. Gold have many good properties to act as a value abstraction, but eventually it becomes limited by its weight, now bitcoin is much better in this regards