What Unusual Object Was Once Used as Currency in Ancient Cultures?

In ancient cultures, particularly among the indigenous peoples of the Pacific Islands, a unique object known as "rai stones" served as a form of currency. These large, circular stones, some weighing over a ton, were quarried from the island of Palau and transported to the island of Yap, where they held significant value. The value of each rai stone was determined not just by its size but also by its history and the effort required to obtain it. Stones that had a complex backstory or were difficult to transport were considered more valuable. Interestingly, these stones were so large that they were not always physically moved; ownership was often transferred through verbal agreement, and the stones could remain in place while the transaction was recognized by the community. This unusual system of currency highlights the diverse ways societies can define value and conduct trade.