The kula ring
The unforgeably scarce kula collectibles doubled as "high power" money and mnemonic for stories and gossip. Many of the goods traded, mostly agricultural products, were available in different seasons, and so could not be traded in kind. Kula collectibles solved this double-coincidence problem as an unforgeabaly costly, wearable (for security), and circulated (literally!) money. Necklaces circulated clockwise, and armshells counter-clockwise, in a very regular pattern. By solving the double-coincidence problem an armshell or necklace would prove more valuable than its cost after only a few trades, but could circulate for decades. Gossip and stories that about prior owners of the collectibles further provided information about upstream credit and liquidity. In other Neolithic cultures collectibles, usually shells, circulated in a less regular pattern but had similar purposes and attributes.