We have multiple options for currency and, just like on Earth today, more than one might exist within a single sovereign power, not to mention the world.
Trading means providing two pigs for one chicken, for example, rather than two pigs for a unit of value or weight. It is the oldest form of exchange. While areas of our world may do this, most will be more sophisticated. Nomadic tribes and less technological cultures may not have developed currency or the means to produce it, meaning manipulation of ore into metal. They may not have manufactured swords, for example. Later in this chapter, we’ll look at determining the value of items, but it’s mostly about supply and demand.
A fictional world means imaginary supply and demand, so we can invent this and never be wrong. That said, an animal that repeatedly produces a commodity, whether wool, milk or eggs has value beyond its own body, which can be used for meat, bone, and more, so take this into account. A plant that can be duplicated (with seeds, for example) is similar. Skilled labor to produce a long-lasting or superior item is also more valuable than, for example, a ram’s horn that only had to be broken off a dead ram.
If rams are common, I might need to give you five of their horns for the tanned leather hide you made from a bear. But if ram horns are used to signal in battle and few rams are around, maybe I’m giving you one horn for two hides. A word of explanation like this adds believability and can be invented in the time it takes to write the sentence. Just be consistent: don’t show a hugely different number of rams existing four chapters later.
Coins have been used as money since antiquity. For fantasy worlds, this is our default currency. Long ago, metal had its value because of weight, quality, and material (like 2 oz. of 14k gold). It relied less on a trade valuation at banks and could be melted down and still have [almost] the same value. A sovereign power minted coins in a standardized process to ensure the weight, then stamped them with an official insignia to establish trust in the coin’s value. One reason is that metals can be impure by accident or on purpose, whether the latter is intended to defraud the unsuspecting or to reduce the amount of precious metal used as money. This impurity can be checked by use of a touchstone, which is a stone tablet that reveals the alloy of soft metals when those are used to write on it.
In time, metal changed from being a unit of weight into one of value. In some countries, only one type of metal (like gold) was used, with different sizes denoting value. Separate regions have access to different quantities of precious metals. This could make things more realistic and more challenging when characters travel between kingdoms.
An issue with coins is their weight; no one carries around two thousand silver pieces, for example, even when they need to. Our world could have iron, copper, gold, and platinum, too. If one platinum equals a thousand silver, then they only need two coins, assuming they can find and exchange these. We may want a conversion like this example, using American money for clarity:
1 iron piece = 10 cents
10 iron pieces = 1 copper = $1
10 coppers = 1 silver = $10
10 silvers = 1 gold = $100
10 gold = 1 platinum = $1000
Coins are typically round for several reasons. The pointed edges of a square or rectangle will wear down with use, possibly lowering weight and therefore value, while also making the now irregularly shaped coin harder to stack. In production, coins were also struck, causing the metal to push outward in a circular shape, which made this a sensible form. A lucrative business could be had shaving off flat sides of a coin, thereby reducing the weight and value, though milling was added around the edge so that it’s easier to tell when the coin’s edge has been shaved (the milling would be gone). The absence of these indicates a less sophisticated culture.
Any gem can be used as money, but can they be a unit of weight? Probably not. How much a gem weighs (how many carats) doesn’t indicate value by itself because the quality can be so poor as to make it largely worthless. Few people have a specialized magnifier (“loupe”) or the training to identify a stone’s quality, making gems less viable as a unit of currency. If people can’t tell the quality, they’ll get manipulated during trading. Despite this, in antiquity, the naked eye was how all gems were appraised, so we can do this, too. Most gem deposits produce low quality stones that will never be fashioned into a jewel. The color and clarity are two elements that determine quality, which can be increased or decreased when the raw stone is carved into a jewel.
An underground race like dwarves would likely mine for gems and minerals, using either one a currency and easily converting values between them. Perhaps one diamond is the equivalent of one platinum piece. Would they have two currencies, or do they represent different spheres of social strata, such as royalty using gems and commoners using coins? A commoner caught with a gem coin might be assumed to be a thief. Maybe every dwarf is given a loupe at birth.
If gems are a unit of value instead, then low grade gems (like amber) can be inscribed with their denomination and function like metal coins. The gems could still be highly polished and look valuable to the naked eye. Even in antiquity, some gems were beautifully carved to show portraits of Roman emperors, including a garland of leaves with the leaf edges clearly visible. They won’t need milling because shaving down a jewel doesn’t produce useful shavings like it does with metal. The coins need not be round as wear on the edges is unlikely.
Compared to metal, gem coin denominations may challenge audience memories due to this being unusual in fiction and less familiarity with gem values on Earth, not to mention values in a fictitious world. By contrast, we all know gold, silver, and copper are progressively less valuable. Regardless, we can create and use a system like this one, with units of value:
|Poor-Quality Stones||High-Quality Stones|
|1 amber = 10 cents
10 amber = 1 jade = $1
10 topaz = 1 amethyst = $100
10 amethysts = 1 opal = $1000
|1 pearl = 10 cents
10 pearls = 1 emerald = $1
10 sapphires = 1 ruby = $100
10 rubies = 1 diamond = $1000
Figure 16 Gems as Currency
Paper money is a unit of value and therefore requires trust and the backing of a bank and/or government. Sovereign powers may be too unstable or short lived for trust to develop paper currency, however. In fantasy worlds, the machinery to mass print paper has not usually been invented, but they can be done in smaller quantities by more physical means, just like coins. Paper money can be easily destroyed in fire, water, or by being torn, but it is easier to carry around in large sums than coins, and in some cases, gems. Keep bills simple, such as ones, fives, tens, and so on. Like some Earth countries, we can change the color per denomination. Bills are typically for larger numbers (dollars) than coins (cents), but there’s no reason this can’t be reversed. They can also be far smaller than what we have on Earth.
Just like today, SF worlds of comparable or superior technology to ours might have credit as currency. This requires official banking by a trusted source, whether a sovereign power on a planet (or elsewhere), a union of powers (possibly across worlds), or an institution that regulates the currency. Today we have bitcoin and other versions of credit, and we can invent more types, but unless we intend to delve into their usage (or the rise and fall of it), we should aim for simplicity. One choice to make is how people access and exchange credit. On Earth we use cards, devices like phones, and computers. What tech might be employed in our world? An iris or face scan? Fingerprints? DNA? An implant?