Personally, I am very interested in what archeology would say about the circumstances that existed when gold turned from just another commodity into a form of money. First of all, to assume that gold was the most valued metal for all ancient, here I am restricting myself to the Mediterranean nations, cultures is a false assumption for the Egyptians valued silver more than gold; nevertheless, this only proves the prior assumption wrong, and does not yield much knowedge. Gold, of course, has its uses as a decorative metal from which it will definately derive value, the fact that gold is one of the easiest metals to work with ensures that gold is definately the optimal metal for an ancient jeweller to work with. The value of gold would definately be augmented by the fact that its durability is unrivalled thus making it probably the most durable good known to man.
It is also necessary to understand that coinage itself did not emerge a bit before 600 B.C., and the first Greek coins appear on Aegina around 595 B.C., and in Athens at around 575. However, as far as being a medum of exchange, the Egyptians before measured the value of surplus goods based on a unit of weight, the deben, which weighed about 90 grams, that was usually calculated in gold, silver, or copper. Also, the Kas shipwreck gives a picture of commerce at around 1100 BC that involved many small quantities of different commodities, thus implying that barter was the primary form of paying for goods. Nevertheless, this does not explain why gold was chosen as a form of money, but the fact that the Egyptians measured debens in gold, silver, and copper, the three being probably the most important metals for the Egyptian economy, displays that the fact gold was a metal was very important for it becoming a form of money. I must admit though that I am unprepared to take this any further; nevertheless there are some important conclusions that can be derived.
I cannot explain above why gold became money, though I do believe I gave a sufficient exposition of how it could possibly turn into money. Also, the nature of social evolution, a decentralized process of trial and error that proceeds across generations to distill the behavior patterns that are the optimal, and most efficient from those that prove unsatisfactory. Eventually, the behaviors that survive will spread across society by other imitating them . It is possible to understand how gold became as entrenched as it is through social evolution because by its very durable, and cannot be counterfeited gold is a great commodity to be used as a money. Eventually, the forms of money, such as the Egyptian copper deben, that prove less satisfactory than gold are abandoned as forms of money that historically eventually result in gold and other specie becoming the dominant form of money across the entire world. In addition individuals are born into a society that has already undergone generations of social evolution, and ergo they are likely to take certain facts for granted. Eventually, they will stop caring about the nonmonetary uses for gold, and instead start valuing it pretty much soley for its monetary worth.
I wish that I could continue this analysis into the post-gold standard world, but I do not have enough time, so I hope what I have wrote provides some light upon the matter at hand.