The biblical word “pieces” may describe fragments of silver, a weighed amount such as a shekel, or a particular coin. Its meaning depends on the passage and the underlying Hebrew or Greek expression. It can therefore refer to something other than separate coined pieces of money.
In Psalm 68:30 “pieces” denotes fragments. In other passages the supplied material supports supplying “shekels,” while the piece of money in Matthew 17:27 is a stater and that in Luke 15:8-9 and Acts 19:19 is a Greek drachma.
Silver was commonly reckoned by weight, and some amounts were broken from bars or larger pieces. The supplied material distinguishes these amounts from coins and identifies the shekel as a common monetary weight.