We're a new group with a DM that's relatively new. In a recent session the party visited a mine and found a cart full of unrefined ore. We pushed it all the way back to town and are now trying to cash it in.
How much GP would 100 pounds of unrefined gold ore be worth?
This is more of an industrial mining question than an RPG one, but pretty much the gaming answer is: whatever you want it to be.
The thing with "gold ore" is that it's a mixture of valuable gold and worthless rock and that ratio decides what you can get for the ore.
Going by this site (which, of course, talks about modern day mining) a chunk of high grade gold ore would be worth as little as $0.75 per pound. At those prices, your whole cart is worth between a few coppers to a few silvers.
However, it's pretty likely that your game is set in a more medieval society, where the gold ore mined is much richer than that, due to less efficient refining techniques only making those worth it. Or, you just want to reward them for their hard work. So you could set it a bit higher; maybe a few gold pieces because of exceptional quality.
But really, gold ore isn't generally very valuable; you need to process a lot of rock to get anywhere. Then again; gold ore normally also just looks like normal rocks, which makes me wonder why your players were hauling it up in the first place... could it be you told them it was visibly sparkling with gold or something? That's certainly the way it's often depicted in games and movies, and would also explain why people think it's valuable. If it was carted up under those assumptions, definitely just make it a valuable thing.
I mean; people expect gold ore to be valuable, even if it isn't, and this is a game. Might as well make it valuable just because that's what everybody expects. That's the good thing about asking on the RPG exchange instead of Earth Sciences or Economics; we get to tell you the price that makes your game most fun. And that should probably match expectations much more than reality.
From a player's perspective: It is worth whatever someone is willing to pay for it, and there's no general way you can predict how much an NPC will be willing to pay for it.
The D&D economy is utter nonsense if you approach it from a simulationist perspective. Price lists are designed to manage how many bonuses player characters have, not to reflect anything that could function as a monetary system.
So, the GM should make unrefined ore whatever value suits their game.
Factors they can consider:
Chapter 7 of the Dungeon Master's Guide has recommended reward levels based on the challenge ratings of the monsters defeated. If following those guidelines, the gold ore should be considered part of the treasure received for defeating the monsters (although that would need planning ahead and it is probably too late to calculate this for this particular case).
It varies with the purity of the ore but on average there is about 1 oz of gold in a ton of ore. 100 lb is 0.05 ton so you have 0.05 oz.
In the Forgotten Realms, 1 gp is about 0.32 oz so you have almost enough to make 0.16 gp. However, currency generally traded at a premium over raw metal - the amount has varied depending on the reputation of the mint. Mints known for diluting their coins could trade at a loss compared to the raw metal.
Let’s say you have 1.5 sp in raw metal but it has to be extracted - which costs, so, somewhere between 0.5 and 1 sp. Effectively, you have 100lb of dirt.
On the plus side, the cart is likely to be worth considerably more than the ore. That’s a win.
Pre-industrial societies without the ability to extract gold with cyanide did not mine ‘ore’. They looked for alluvial gold, either washed out by water or accumulated in nuggets or in veins running through other minerals, usually quartz, where natural forces had done the work of refining it.
D&D is a game not an economy. The DM gave this to you as treasure so it’s worth the amount that the DM wanted to give you.
This is entirely dependent on what you mean by "ore". Gold dug out of the ground varies from nuggets (placer), which just have to be melted, to rocks that need chemical (cyanide) processing to recover anything.
In the real world, the price difference ranges from $27 per gram for the best nuggets to pennies per pound for the lowest grade ores. However without magic, they would not be extracting chemical ores (invented in 1880) or ores that need industrial levels of mechanical extraction, So you are dealing with relatively high purity fire extractable ores as a minimum.
According to this question converting US dollars to GP is tricky (anywhere from $0.15 - $200)
But according to the Player's Handbook (pg 157), 1lb of gold is worth 50gp
Placer (nuggets) gold is typically between 70-90% pure; on the other hand, minable, fire-extractable ores can be as little as 0.0031% gold (quartzgold). So your value ranges from 4500gp to 15gp, maybe even less if you account for the cost to extract it from the ore.
Given that we are talking about a mining cart, I would favor a lower value since no one would be able to move a mine cart full of placer gold. Plus, a mine producing mining carts full of placer gold would be the most valuable mine ever found by a huge margin.
If 1gp = 10sp, then gold must be about six times as common in a D&D world as it is in the real world. Real-world estimates grant the idea that 1 ton of ore yields 1 troy ounce of gold, so 1 ton of D&D gold ore should yield six troy ounces, or just under 0.4 pounds. That's enough to make 20 gold pieces from a ton of ore, so if we discount the costs of refining and minting, 100 pounds of unrefined gold ore should be worth about 1gp, give or take a few coppers.
Yeah, that's not much fun. I suggest making something about the ore "special" to increase its value, or substituting another reward. Or just invoking Rule 0 to disregard the economics and setting a higher value because the DM said so. The PCs aren't all that likely to care about the economics of gold mining anyway.
Alternatively, play this for comedy. Keep the ore at 1gp, and add other rewards so that the total hoard is worth what would be appropriate for the encounter, but don't tell them the ore's value yet. When they finally finish hauling the ore into the goldsmiths, the buyer looks at them with a long-suffering sigh. "You know, you would not believe how many adventurers we get carting in loads of ore and thinking they're going to get rich. Do they teach you anything about the economics of gold mining at... hero... school... or wherever you all go to learn how to do all those hero-y things? It takes..." and the buyer launches into a boring lecture that probably isn't really worth going into. They get the fair value of the gold, since it is nonzero, but it's a silly moment that they'll probably remember for a lot longer than just cashing in.
This is all from a DM's perspective. I can't tell you what your own DM is thinking. Maybe one of these, or maybe something else.
I'm going to take a different tack on this. Ultimately, if you want this to fit into the game you need to use the "tools" they've given otherwise you're going to get weird results. Specifically: If you make this too valuable, they're going to quit being adventurers and start being gold miners. (If you make it too cheap, no one would mine gold).
Let's pretend that there's a set of "Artisan Tools" for mining. (There isn't). If there were, then this would be a case of: How many men did it take to mine this gold over how many days. Knowing that answer gives you exactly how much it's worth: 1 gold, per miner, per day. This comes from Chapter 8, Downtime Activities, Practicing a Profession.
So, in other words, if there were 5 miners and it took them 5 days to fill the cart, it's worth (to sell to someone who will process it) 25 gold.
By the way, by extension, refining it should use the same concepts... it should take 1 person 1 day to refine ore into 1 gp worth of gold using the appropriate "Artisan Tools" (which also do not exist).
As a personal note: I like the other answers too, but, I think this approach will flow better with the game mechanics than trying to reverse engineer real world answers into the game... which typically works very poorly.
