[inawarminister]

There's also cowry-as-coinage, which seems to be very old and very distributed (Africans, Arabs, Indians, Southeast Asians, and East Asians were still using cowry for international trade to the dawn of the Industrial Age)

Indeed, the Chinese kanji for money stems from Cowry. 貝

[0] https://en.wikipedia.org/wiki/Shell_money

[1] https://en.m.wiktionary.org/wiki/%E8%B2%9D

Incidentally, as an Indonesian, I just recognized the shells we children used to play was exactly this species! Ancient currency, of which millions from thousands of disparate culture used to toil and fight for, used for children game tokens... Haha.

[throw0101c]

See also the use of giant rocks as currency:

* https://en.wikipedia.org/wiki/Rai_stones

Generally anything can be used as money if people agree to it. There is nothing inherent in in gold/silver/shells/whatever that make them "money".