So, I found myself regarding the value of coins in Dwarf Fortress, especially in adventure mode, and the kind of buying power they have in-game. What better to compare them to ancient Rome? Tempting as it was to use the values of the olden days, when 1 denarius was 25 aurei, it's hard to get a reliable source of the prices for goods back in those days. So instead, I used a more extreme example of value, or the lack thereof, to compare DF coinage to.
As usual, if my math, DFWiki magic, or historical accuracy is FUBAR in some way, feel free to point and laugh.
EDIT: Some corrections to be found. Seems I was using half as much of volume as I should be, should use the k. mod. instead of the regular modius. This sharply changes the implications of DF flour pricing.
In response to the growing inflation and poverty in the Roman Empire, in the year 301 emperor Diocletian issued the Edict of Maximum Prices. This laid down price limits for various goods, which if exceeded would lead to harsh penalties for both buyer and seller.
Figures listed where given in a unit termed denarii communes, a form of notational currency. The physical silver denarius had varying values, weights, and silver content through the history of Rome, steadily devalued over time, and therefore d.c. was used in several imperial edicts to provide a consistent legal currency, and the coinage of the time would be valued in relation to it.
The values set for grain were based on the modius castrensis, a unit of dry measure (volume). This was roughly 12.93 liters. With handfuls of powder having a volume of 200 milliliters, that's 64.65 handfuls of powder in DF terms.
Unlike with flour in DF, the prices given varied from grain to grain. Oats and hayseed were relatively cheap 30 d.c. per k. modius. Sesame and hulled rice were an impressive 200 d.c./k.modius. Several items were set to a higher value if processed first, as the latter indicates. Hulled millet bumped up the value from 50 d.c. to 100 d.c.; while broad beans were 60 d.c. unshelled, 100 d.c. shelled.
But luckily for us, many of the prices for dry goods were fixed at a nice 100 d.c. per k.modius, including good old wheat. So the net result of this was that 1 nice, DF-style handful of wheat would run you about 1.55 d.c.
So, what's that mean compared to how much value a silver coin has in Dwarf Fortress? In adventure mode at least, every civ gives silver coins a value of 5 dorfbux, one hell of an increase over its raw material value. Handfuls of powder have an item value of 1, while the various flours tend to have a material value of 20. So, that's 4 silvers if you want to buy a handful of flour, while that modius would be an obscene 258.6 silvers (assuming we equate 1 silver as 1 d.c., second post gives a good reason not to).
But what about other goods? Meat's one instance where the average adventurer can live like a king, even if they aren't hunting their own game. The prices for meat in the Edict were by weight rather than volume, specifically the libra, equivalent to about 328.9 grams. 1 libra of beef or goat was fixed at 8 d.c, while chickens and several other animals were sold individually instead of by the pound. Pork, lamb, and venison were set to 12 d.c/libra. This would be a good price for our average, since most of the domestic animals have the same values for their meat.
1 piece of meat in DF has that familiar old 200 ml volume, while muscle has 1060 density, for a weight of 2120 grams, or roughly 6.446 libras. Yes, that value made me say "holy shit" too, until I realized that meat does indeed say it's 2 kilos in your inventory. If we assume that this density is accurate, this means a libra is about 31 milliliters. So by Diocletian's Edict, the 100 d.c. that gets you almost 19 liters of wheat would buy you around 258.33 milliliters of pork. By volume, pork was almost 50 times more expensive than wheat! Yes, this is way worse than when I thought these prices were using the Italian modius.
Now, compare to how meat has a material value of 1, and an item value of 2. That means 1 silver will buy 2.5 units of meat, yielding 5300 grams. That means in Dwarf Fortress, wheat is 10 times more expensive than pork by volume.
What about some booze? Wine is a classic Roman favorite. Prices were fixed for liquid measures in sextarii, being 546 milliliters. Since DF booze doesn't have quality levels, we'll use the figure of 8 d.c. for a sextarius of "vin ordinare" or ordinary wine.
Good old grape wine in DF has a material value of 2, and 60 mL of liquid has an item value of 1. So that sextarius would cost 1.82 silvers in DF, which is even cheaper than the price limit on beer.
Speaking of which, how about some nice, cheap beer? Want barley, or wheat? The former is a mere 2 d.c/sextarius, while the latter is fixed at 4. With most of the beers in DF having the same 2 material value as wine, so the value there is perfectly within the limits set by the Edict.
What about some clothes? Cloth was often rather expensive back in the day. You could get a winter (most likely wool) tunic, meant for a solider, for 75 d.c. Or how about a libra of wool for the same price? Or for only 72 d.c. you can get a libra of the lowest-quality linen. Want some silk? 1 libra will cost you 12000 d.c. Don't even ask about having it dyed purple. That's for use at the direction of the emperor only (on pain of death, naturally), and even then it'll cost a hefty 150000 for those 328.9 grams.
In DF, a no-quality sheep wool tunic has an item value of 16, and wool has a material value of 1. Pretty cheap. 1 stack of freshly-woven cloth has a volume of 30 and item value of 7, which at wool's density is 150 grams, and a value of 1.4 silver (making a libra of wool about 3 silvers). Meanwhile regular old cave spider silk is the same price (what a steal!) while even GCS silk is only 12 silver to the libra. Linen has a material value of 2, so that's only 6 silvers per libra.
As for dying, no purple dye yet, but midnight blue dimple dye is perhaps the closest in color. Most of the dyes have a material value of 20, and (if the wiki's correct) adding dye counts as adding the item value of powder (1), but (unlike the norm) is subject to quality multipliers. So assuming your dwarven king orders a patch of master-quality cave spider silk dyed with masterfully-applied dimple dye, that's only 76.8 silvers per stack of cloth, or 168.39 silvers per libra.
Want some leather? Sadly the sources I could find didn't give an explicit volume for the prices on hides, but leather in DF is also quite nebulous in how much you can do with any given piece of leather, which rabbit and oxen leather both having the same utility.
Tanned oxen hide of second quality is listed at 400 d.c., while tanned deer skin is maxed at 100, wolf leather at 40, and goat leather of the largest size (whatever that implies in the translation) being 50.
In DF, leather has a fixed item value of 5. Oxen being a term for particular sort of bovine, we'll use cows for that. Lacking any changing to leather's default material value of 1, the whole hide will only cost you 1 silver. The same applies to goats and deer. Wolves have a material value of 2 applied, so this means their pelts will fetch 2 silver.
So now, a while back I mentioned the value of non-silver coins, with DF gold coins being only 3 times the value of silver coins. The gold coin issued (though in limited numbers) by Diocletian was the solidus, containing around 5.5 grams of gold. This replaced the aureus that had varied in size over time, but (unlike the denarius) retained more consistent purity. When Caesar was around he standardized the size of the aureus at about 8 grams.
Whereas in the early days 25 denarii (having 4.5 grams of silver when introduced) made for 1 aureus, Diocletian tariffed the solidus to 1000 denarii communes. By this point the silver content of the denarii in use was a mere 5% in a coin weighing 3.41 grams. That'd make for 170.5 grams of silver to equal 8 grams of gold, or 21.31-to-1 ratio by weight.
So in the old days, those 25 coins made for 112.55 grams of silver to 5.5 grams of gold, for a 20.45-to-1 ratio.
Now for Dwarf Fortress coins. Each coin has a meager 0.0625 mL volume, making the silver coins 6.55 grams in weight and the gold ones 12.075 grams. The end result is a by-weight value ratio of roughly 1.627-to-1.
Not that this trivia ignores some important considerations that're covered in better detail in my second post.
So what's there to learn from all that? Honestly, not much. Amusing as it'd be to make a "realistic pricing" mod, there's little real need for such. If one intends to do so, then perhaps that'd be useful information for someone.
Other that that, it's more for some amusing comparisons, because I am a neeeerd.
Source, english translation of Ēdictum Dē Pretiīs Rērum Vēnālium:
https://www.academia.edu/23644199/New_English_translation_of_the_Price_Edict_of_Diocletianus
