Here is a short video that examines early forms of money such as metal and salt. Of special interest, it shows the transition from barter goods (such as axes) to transactions facilitated with miniature ax heads without handles or any use value. By creating miniature ax heads they created a money that was valuable and more divisible than the full size ax. By forming metal such as bronze into the form of a miniature ax head they alerted potential traders of its commodity value. This was a step towards coined money.
Going Money
