Extremely curious is the case of the inhabitants of the Yap island, in Micronesia, who for many years used as money (and they still use to some extent) Rai stones, large circular disks of limestone with a hole in the center.

The people of Yap quarried the limestone rocks from a location on the mainland, Palau, about 400 km away and brought them to their island in canoes and rafts. Since it was not on their island and was difficult to transport, limestone was an extremely valuable commodity for them. The larger the stone and the more difficult it had been to extract and transport, the greater their value.

The amazing thing about this form of money is that once transported to the island, the heavy stone disks were exchanged for all kinds of goods but were hardly ever moved again. There was no need: everyone knew to whom each stone belonged. Even in case they were lost in the sea during transport, as sometimes happened, they were still used as currency knowing that those particular stones were at the bottom of the sea.

This aspect of “everybody knows everything” is why they are often associated with modern Bitcoin, in which the record of all transactions (blockchain) is distributed to the entire network and it determines the owner of each coin.

What caused the decline of Rai Stones?

After about 500 years, this form of money later suffered its own inflation when, in the early 20th century, an Irish-American shipwrecked near Yap was helped by the natives. As a reward he provided iron tools that made the production of Rai coins easier. As the relationship with the Europeans intensified, the people of Yap also began to do business with them in order to use their boats to transport the heavy round stones. However, these new stones produced with the help of iron and transported by European boats were considered of less value than the ancient ones. Although still used on specific occasions such as marriages, alliances or political affairs, they have gradually been replaced by more modern forms of money.