Brilliant work @itchykitten
A fascinating perspective as ever.
Money can be anything people perceive as having intrinsic value. This is the reason why gold and silver have always been coveted. Examples of more interesting things used are seashells and tea.
These are cowrie shells from China 16th-8th century BC

And this is a tea brick used in Mongolia and Siberia up until the 19th century.

The history of money is completely different to that taught in modern economics class's. This is due to the insistence of teaching Keynsian economics which is the reason our economies are in such dire trouble, the promotion of debt creation.
A pure barter society is a nice theory but not practical as you suggest, thus people were forced to come up with an accepted medium of exchange.
Different peoples coveted different things and therefore the history of money is a fascinating subject as you so brilliantly show.