“The value of stone money has always been fluid, challenging the Western concept that currency value is pre-determined and fixed”
The value of commodities and real estate continually change in relation to currencies and each other.
“The coins are valued by their size – they range from 7cm to 3.6m in diameter – as well as their ornateness and even for the sheer difficulty in obtaining the rock. How much a coin is worth also depends on who you give it to, and what for.”
Sounds similar to gemstones or jewelry. What if these stones were faceted and fit on a ring? It doesn’t sound to me like this is a currency system. It’s simply assets that they use for trade.