While gold and silver have historically been best favored as preferred forms of commodity money, a great many other surprising commodities have also been used. In some cases, the commodity monies of choice could be eaten instead of spent or saved. Mongolians, for example, used bricks of tea as money, and Norwegians at one point used butter. At times in the medieval period, the Norwegians also used dried cod as money, which they exchanged for both coins and goods when transacting with Hanseatic merchants in Bergen. The Hanseatic merchants, in turn, sold the dried cod in southern Europe, where the fish were in high demand for religious rites. 

Salt Money

Salt productionCredit: Creative Commons photograph by Tomasz Sienicki licensed under CC BY 3.0Salt is a vital commodity that is necessary for human survival, and which has also been used as money in many places. While salt's abundance and ready availability is largely taken for granted in most modern civilizations, such was not always the case. In medieval times — particularly to those living in Northern climes — salt was vitally essential to procure large amounts of salt for curing meats for storage, and control of salt mines was often a key determinant to political power as well as wealth. The English word salary is derived from the Latin salarium, designating a soldier's allowance to buy salt. Salt was also used as money in China, North Africa, and the Mediterranean.

Salt CrystalsCredit: Creative Commons photograph by Mark Schellhase, licensed under CC BY-SA 3.0Some of world's purest salt from the Central Sahara was mined out of salt mines in large slabs that might be as large as three feet long and several inches thick. The salt was then carved into bars suitable for serving as a monetary medium of exchange. These were later wrapped in coverings, in order to prevent any mischievous chipping or scraping of the salt between trades— which would have been equivalent to the ancient trick of shaving small amounts of gold or silver off the edges of coins. Miners in certain mysterious West African gold mining regions (which both Arabian and Portuguese traders coveted possession of for many years, but were unable to discover or conquer) once traded their gold ounce for ounce for salt, which the miners depended on for survival.

Parmesan Cheese as Bank Collateral

Many other forms of spices and foodstuffs have also been used as money. Even as unlikely a form of commodity as Pamigiano cheese has been accepted as bank collateral in Italy for centuries. Italian bankers have apparently been using Pamigiano (or similar forms of parmesan cheese) in monetary transactions since the Middle Ages. This was convenient due to the cheese's high value to weight ratio, and the fact that the cheese's long aging process usually made it necessary for producers to borrow money before the cheese could be brought to the market for sale. Even if the borrower defaulted, the banks could limit their losses by selling the valuable cheese that they had claimed as collateral for the loans. 

Parmesan CollateralCredit: Creative Commons photograph by Wittylama, licensed under CC BY-SA 4.0 The modern regional bank of Credito Emiliano held 17,000 tons of parmesan cheese as collateral for loans as recently as 2009. The 440,000 wheels of cheese held by the bank were reportedly valued at about €132 million euros (which would be equivalent to around $147 million dollars at more recent exchange rates). Like gold bars, each 80 pound wheel of cheese was branded with a unique serial number, so that the cheese could be traced if it was stolen. On one occasion, a group of thieves tunneled into one of the bank's climate-controlled warehouses and stole over 500 wheels of parmesan— but were reportedly captured by the authorities before they succeeded in grating the cheese and making it untraceable.

Gold, Silver, and Monetary Metals in More Unusual Forms

Gold & SilverCredit: Creative Commons photography by Classical Numismatic Group, Inc., licensed under CC BY-SA 3.0 Gold and silver have stood out markedly throughout history as ideal forms of hard currency, and were often independently chosen by distant cultures for use as money. These metals are long-lasting (seeming virtually eternal in contrast to human lifespans), and are consequently a superb store of value. They are also capable of being assayed to determine their purity, and are easily divisible by metalsmiths into smaller or larger pieces. They are consequently excellent as a means of exchange and measure of value. Gold, silver, electrum, and other "precious metals" also have a high proportion of value to weight (making them very convenient as a medium of exchange), and in many cases they are even capable of being melted down and recast into a different form that still holds its value, by virtue of the metal content itself.

However, far more obscure and idiosyncratic forms of metallic money have been devised through the ages. Fine gold and silver coinage was introduced to the Greeks as the legacy of the fallen kingdom of Lydia, but the Spartan lawgiver Lycurgus was reputed to spurn the use of gold and silver coinage to such a pronounced degree that at one time he decreed that only large and unwieldy pieces of iron bullion could be used as a monetary medium of exchange, in order to inhibit the spread of commercialism. Han Dynasty CoinCredit: Creative Commons photograph by Randy Benzie, released into the public domain. Long before this display of Spartan puritanism, the fundamental Greek monetary weight measure, the drachma, was also based on the use of iron money in Greece: The drachma originally designated the a handful of the iron "oboloi" spits that the ancient Greeks once used as money. The Ancient Chinese also had a notable history of using base metal knife money and base metal token coins, prior to the ascension of silver as a preferred form of money. 

Bronze Cross Money, Iron Snake Money, and Iron Money with a Spirit

Katanga CrossCredit: Creative Commons photography by Plutho, licensed under CC BY-SA 3.0 A number of particularly unique forms of base metal money have come from Africa. One of these is the Katanga cross, an ancient form of money cast from copper. The Katanga crosses carried no uniform weight, but ranged between 1 to 2.5 pounds, and were also associated with ancient rituals in which they were buried with the dead. During the brief period during which Katanga became an independent nation in the 1960s, the government issued national coins depicting the much more ancient Katanga cross money that had preceded it.

Lobi SnakeCredit: Creative Commons photography by Sean Pathasema/Birmingham Museum of Art, licensed under CC BY 3.0 The Katanga crosses were by no means the strangest forms of African base-metal money:  Ancient Bafian potato mashers were another iron implement used as money in Cameroon, mainly for rare, high-value transactions. According to one account, wives could at one time be bought and sold at the approximate rate of thirty Bafian potato mashers each. In Ancient Ghana, iron snakes known as Lobi snakes were forged as occult talismans to repel poisonous snakes, and were also used as money in trades and exchanges.

Kissi PenniesCredit: Creative Commons photograph by Brooklyn Museum, licensed under CC BY 3.0Another form of iron money, notable for being regarded as "money with a soul," were the"kissi pennies" of West Africa. These were long strips of iron crafted into a distinctive shape, but of varying length— with longer strips representing higher value. When placed over the graves or tombs of the deceased, the kissi pennies were believed to become the dwelling places of spirits. The kissi penny's odd but distinct shape may have provided better measure against debasement, due to the greater difficulty in making illicit alterations of the metal without leaving obvious traces. As some of the pennies were said to contain spirits, a broken kissi penny could sometimes not be used again without first engaging a witchdoctor to perform ceremonial proceedings, in order to reforge the unit of money and restore its spirit prior to further use.