A commodity money is a medium of exchange the units of which are fixed amounts of an actual commodity that has value other than as money alone.
Many items have been used as commodity money such as conch shells, barley, beads etc., as well as many other things that are thought of as having value.
Historically, silver and gold coins of known, standard weights and designs have emerged as the preferred commodity monies of the entire civilized world. Gold and silver have been used as money throughout most of recorded history, even as far back as Abraham [Genesis 23:12-16].
In the case of a commodity money, the actual commodity – silver or gold – is both the medium of exchange and the standard of value (that is, the unit in which prices are stated in the marketplace).
For those of us who use the Bible as our foundation, it’s interesting to note that throughout scripture silver and money are pretty much synonymous. The Hebrew term that means “silver” is found 403 times in the Old Testament, and depending upon the context, the KJV translators translated it into either silver or money 399 times. In essence, silver and money were the same idea, the same concept, the same thing, as it were.
Thus, Biblical money is Silver.