Turning iron into gold

As part of my ongoing quest to become the ultimate dwarf, I've been using Aryxymaraki's excellent mining rules to tear veins of iron, tin, and copper from the living earth. So far, it's going well. And yet, I am troubled.

I feel weird about just selling the metal. My dwarven instinct (read: avarice) tells me I should be doing something with these minerals before selling them, and my local craftspriest suggests that that something is crafting fine weapons and armour. Having no talent as an armourer myself, I sought out and hired the best I could find, with the plan of supplying them with raw materials and selling or keeping the crafted goods they produce - and yet I find myself puzzled.

You see, I know that a master armourer can produce 40 gp of armour and weapons each month; And I know that I must pay them a wage of 75 gp for each such period. I had always assumed that some of that coin went to buy the raw materials an armourer uses to ply his trade. However, a reasonably-trustworthy human of my aquaintence says he pays only a palty sum for the upkeep on his own slave armourer - yet that slave seems to produce the same 40 gp worth of weapons and armour as my free dwarf, even without coin for materials! Surely he cannot be producing unworked ingots from thin air - yet that is what his accounts say. As for my own armourer, I'm at a loss as to how much less I should be paying him. I cannot trust his word when gold is at stake, of course - yet I cannot trust my human aquaintence's accounting, either.

Help me, Autarchs! Is the human's slave armourer crafting a little extra on the side, to pay for metal?
And as for my own armourer - how much can I save on wages if I provide him with regular loads of common metal in lieu of some pay? How much of a load can he use up each month?

(More broadly, this could apply to other crafting proficiencies that players are likely to use, such as gem-cutting and jeweling, so this'll come up a lot with my production-minded players.)

Here ya go:



Wow, that answers all my questions extremely efficiently.

So, all I have to do is calculate the amount created by my armourer(s) each month, divide it by four, and assume that that much is the cost of materials? Easy! That gives me everything I need to work out how quickly I'll run through loads of common metal, as well as how much to reduce my armourers' wages by. (Incidentally, it also suggests that uncut gems should be worth 1/4 of their cut value, which was something I was wondering about.)

Thanks! (I'll also let my human aquaintence know that he doesn't need to torture his slave. He was wondering.)

You may have noticed me rambling about gems in the mining rules.

Making them worth 25% of their uncut value doesn’t help me that much, because of the existence of very high GP value gems.

Let’s say you have a 5,000 gp value gem. You found this as loot. It’s cut, it’s worth five grand. Now let’s consider its providence.

At 40 gp/month, it would take a master craftsman (6000 * 3/4 = 4500, divided by 40) 112.5 months to cut that gem, even having been already provided with it. (Its value being 1,500 gp uncut.)

The idea that this gem might have required just over nine years to be cut bothers me. A lot. Maybe if it were a unique one of a kind amazing gem, but you can find these things by the truckload in dragon hoards. (Ok, maybe truckload is overselling it, but this isn’t even the top category of gem value. It’s not even the second-highest. It’s the third most valuable gem type. And granted brilliants are somewhat rare, but still, I don’t feel like they’re rare enough to justify requiring approximately ten years of work from a master to cut.)

My own solution was to base their 40 gp on the uncut value of the gems, and to say that an uncut gem is 1/10th its cut value. It has its own problems (most notably, obscene profit margins for gem cutters who are being fed gems from a mine), but it cuts most gem cuts down to a year or two, and I’m ok with the idea of brilliant gems taking a year or two to cut.

And gemstone mines are rare enough that I’m kind of ok with the idea of them offering obscene profit margins in the right circumstance.

Yeah, I guess the abstraction's a bit leaky when it comes to materials of high intrinsic value, since realistically the materials cost of goods made out of those materials should be a much greater portion of the overall cost of production, all other things being equal. (Solid silver forks shouldn't require any more labour than copper ones, for instance.) You can cheat a little by claiming that the extra cost and labour goes into ornamentation and "getting it right when the stakes are higher," but that still doesn't account for enough with the really extremely valuable substances.

I guess I could claim to my players that a gem cutter mostly cuts low-value stones, since you can't cut too many massive rubies without the massive uncut ruby supply drying up. Then I could say that the limited gp earned per month cost just indicates the difficulty a gem cutter has saving up enough by selling other gems to buy the giant uncut ruby he wants, and that actually cutting that ruby doesn't take that much longer than any other gem. Then I could claim that a gem cutter can cut a specific number of gems per unit time (say, one gem for every 10 gp of value he'd normally be able to earn). That's not too unlike how I've heard gem cutting has worked throughout history (profit margins weren't that much better than jobs working with less valuable materials, since clientele teneded to be rich and powerful enough that disagreeing with the prices they demanded was dangeorus). I guess that kind of reduce the need for a gem cutter for your mine to a rubber stamp, though. Hmm.

Perhaps, rather than generating specific gems, mines could generate loads of the "semi-precious stones" trade goods? That might allow you to sidestep the issue. (I don't have my books on me to check the trade goods table, alas.)

That’s fundamentally how the metal mines work (the varying amount of ore mined per week was selected so that they would fill up the metal trade good at differing rates, but in the end, that’s what they all spit out). The problem I have with that is that it doesn’t allow for the finding of extremely valuable gems in any sane fashion.

A load of semiprecious stones is a box (1 stone in weight) worth 1,000 GP. A load of gems is a box (1 stone in weight) worth 3,000 GP.

There are gem values on treasure tables going up to 10,000 GP for a single gem.

Now granted, the 10,000 gp stones are the equivalent of “fist-sized diamond” and should be rare even from a diamond mine, but a single cut 10,000 gp gem is three and a third loads of the gem trade good. And it’s a pretty strange mine that would come up with a single gem in a week, even if that gem is extremely high in quality.

Honestly I’ve never been entirely satisfied with the gem rules anyway, because it’s also a very strange mine that produces only one class of gemstone. More realistically, you would have a percentage chance each week of finding varying kinds of stone, and I’d probably alter it by a quality rating to mess with the probabilities on a per-mine basis. This still isn’t entirely realistic because it would be pretty weird to be able to find sapphires, jaspers, topazes, diamonds, and rubies all in the same mine in reality (among other gems), so I would also want to change its own gem generation table to limit a mine to having gems in the same family under the theory that the heat, pressure, and available minerals are a function of the location the mine is in and tend to be similar across the mine…

And at this point you see why I gave up and left it with something I didn’t entirely like, because this is not entirely a small task, and gemstone mines are extremely rare to start with.

Fair enough; You are kinda getting into Dwarf Fortress levels of simulation, there.

Unfortunately, now that I've started thinking about this, I've forgotten how to stop. Maybe a gem mine should produce loads of semi-precious stones and gems as I suggested above, and also a few randomly determined gems? That would allow the best of both worlds - but it'd be extra bookkeeping for very little benefit, and wouldn't solve the how-many-gemcutter-hours question.

Or maybe I should treat gemcutting as a profession rather than a crafting ability, and assume all gemcutters work on comission rather than producing goods to sell? That... Well, it sounds a bit counter-intuitive and unlikely, to be honest.


These forums have the problem that many threads have a low "Mean Time to Dwarf Fortress-esque Rules" or MTTDFR

Hum. So, theoretically, you don't necessarily know what you're going to be able to cut out of a hunk of gemstone - I'm sure master lapidaries have a damn good idea but, still. Let's go with that.

What if the uncut value is the average value of each type? Ornamentals, 30; Gems, 200; Brilliants, 4000.

And that's your input to your lapidaries - a "mining load" of uncut gemstone equal to that value.

Then the lapidaries do their work, and at the end, you roll on the Gem Value table.

For each type then:

Chance Value
11.25% 10
58.75% 25
average 30
30% 50

There's a 70% chance you're going to lose money on ornamentals - rolling under average.

Chance Value
10% 10
15% 25
15% 50
15% 75
15% 100
average 200
10% 250
10% 500
5% 750
5% 1000

Again, 70% chance you're under average (sounds funny, I know)

Chance Value
10% 500
5% 750
5% 1000
10% 1500
15% 2000
average 4000
20% 4000
20% 6000
10% 8000
5% 10000

45% chance you are under average - brilliants are the best bet if you can find them.

Makes it into a bit of a betting game. Sure, you've got that uncut fist-sized emerald, but there's a hidden flaw and it turns out only being worth 500gp 10% of the time (maybe as a set of smaller cut stones, or whatnot, rather than something you top a crown with) but you still paid 4,000GP in labor/time for it all.

On average worldwide it equals out. For the prospecting PC, however, it's a terrifying ordeal of possibly thousands of wasted gold. Good fun!



Maybe I should try to acquire the Dwarf Fortress license!

I like this idea a lot. I think it can be expanded into a solid solution.

The value of the uncut gem might not be the average per se, but the idea that every uncut gem of a specific category has the same value. (Or it might be the average. Depends on spreadsheets!) That introduces the gambling element you called out, as well as solving the ‘ten years to cut’ problem. (I don’t mind so much taking most of a year for a rare and valuable gem, you’re being careful with those.)

The quality of the mine can modify the roll on the gem value table somehow…hm. I just had an idea. The gem value table is all the same table, you just roll different dice on it for the different classes of gems. What if mines weren’t differentiated by their class of output, but more granularly by their quality? There would be a table: Mine Quality vs Roll for Gem Value. (So a quality 1 mine might roll 1d10 while a quality 10 mine rolls d100 + 100. Off the top of my head.) Mines could be further differentiated by the quantity of output; you might have a really useless quality 1 mine that produces 1d4 gems per week that is not worth keeping open most of the time, versus a blood-soaked warzone that, if it were ever controlled by someone strong enough to keep the war away from it, could produce 2d20 quality 10 gems per week.

The drawback to this is that since there’s overlap on the gem table in different qualities, you can’t define them purely by value and maintain the ‘same time to cut each category’. So the quality table would also need to tell you what class of gemstone comes out, which I would base on which die roll it’s closest to.

Soon, at the offices of Autarch, LLC:

I reckon it shouldn't "even out;" if the cost of cutting a gem is equal to the average value of a gem, you might as well just sell the uncut gem and save having a gem cutter at all.

Rather, assume that every uncut gem costs a specific fraction of the average cut value (I'll say 1/4, but 1/10 would be equally viable), and make the cost of cutting a gem is 3/4 of the average value of a cut gem of that category - such that cutting an ornamental (average 30 gp) requires 22.5 gp of gemcutter labour, cutting a gem (average 200 gp) requires 150 gp of labour, and cutting a brilliant (average 4000) takes 3000 gp of labour. That makes it so that the value add of a gem cutter is (on average) equal to that of other artisans. It's still possible for a gem to end up being worth less cut than it was uncut, but statistically there's still a value add. Otherwise, there's no benefit to having a gem cutter other than the opportunity to gamble. 

I would apply the "raw materials are 25% of value" here - uncut ornamentals are worth 7.5 gp, gems 50, and brilliants 1000. There's still a chance of losing value on gems and brilliants due to the cutter botching the job (or a hidden flaw), but in general it's a good idea to try to turn them into cut stones. It's still a betting game, but one that favors the players (or the merchants who buy raw gems to have turned into cut stones).

And I really should have read GMJoe's reply above mine and saved myself the effort.