Tales of Tolgard
The monetary system of Materia is based upon a valuable metal system. The actual units of currency are all coins. These system allows commerce to occur all over Materia as almost everyone recognizes the value of these coins.
The base unit of prices all over the world is gold pieces. In fact, for hundreds of years that was the highest denomination coin. However, as wealth grew, merchants began to complain that it was getting ridiculously difficult to move even a small fraction of their wealth. It was then decided that a higher denomination coin was needed. Although the competition was fierce between mithral and platinum, in the end platinum coins won out. Still, to this day, all prices are quoted in gold pieces.
As fortunes have continued to grow, even more wealth can now be transported with the help of the gemstone system.