So, help me out here. Plate Armor is 1,500gp, for +18 AC. Splint is only 1 less AC for 200gp. That's 1,300 for 1 more AC.
Meanwhile a Cloak of Protection should be 500gp, max, according to the suggested guide? And it gets you +1 to saves as well.
Additionally, heavy armor is much more restricted in who can use it than magic items that grant AC bonuses, so in theory, there should be a discount for the armor. And since a heavy armor wearer can't really increase their AC by raising DEX or another stat like some classes can, often its only choice is to improve armor.
How do people manage prices with situations like this?
I usually don't try to find big reasons behind cost of Equipment or Magic Items, and I tend to follow what the book says. But I'd note that the Dex cap also matters when balancing AC.
Well, first thing is to not include the cloak in the comparison, as magic items are never guaranteed to be for sale. But the cost is really a game balance factor. It’s priced so that characters won’t realistically get it before level 3 or 4 (ish). And monster attack bonuses are balanced around hitting certain AC scores at certain points. So you don’t have level 1 or 2 characters running around with an AC 21 (plate + shield + defensive fighting style) so your typical goblin, or kobold or wolf with only a +4 to hit barely has a chance.
I guess I don't understand the question. Price has very little to do with the utility of something. Plate armor is expensive because it's insanely difficult to make using the presumed technology of most DND settings.
A spyglass costs about 1000gp. This is because grinding and polishing glass to precise specifications is difficult. Spyglasses are not terribly useful to adventurers in relation to their cost.
Okay. I mean I've only been playing a D&D a year, so I am still learning. But I guess the idea that utility would have little bearing on price seems odd, both in a fantasy world and in the real world. Like demand is a thing, right?
As for the Cloak comparison, I guess, sure, it not being guaranteed is a thing. Though at the three tables I'm at, the DM does ask the players what items they are looking to purchase. Not all items are made available, but most are. The Cloak is an uncommon item, which from what I've read is intended for tier 1 or 2 levels of play? So I thought it was a fair comparison. As I laid out, with Splint at 200gp, the next jump in armor costs 1,500, but the cloak is at most 1/3 of that and grants you the +1 AC and +1 to all saves to boot. Also, I get non-linear price increases, but the heavy armor prices basically double and then more than septuple from Splint to Plate. Maybe if Plate did something a little more?
Dunno. I just happen to have two level 8/9 characters chilling in Splint Armor, a few hundred gold. So I am of course aiming for the 500gp max Cloak of Protection for both AC & save bonuses, rather than improving my armor. Which is cool. But just feels odd.
Demand is absolutely a thing. Gucci handbags aren't more expensive because they offer more utility compared to a Walmart handbag. In most cases, the Walmart handbag actually offers more utility. More pockets and such. But, like plate armor, Gucci handbags are much more expensive to produce, and much more rare. In the real medieval period, full plate was a luxury item. It was a status symbol. Full plate was almost never worn to battle. That's one of the reasons a lot of plate armor survives to this day. It was simply too expensive to risk damaging it.
I think a lot of people come at roleplaying games from a video game background, where cost of an item is almost always directly related to it's utility. But D&D is a storytelling environment. It's much more important that the environment be believable in a narrative story. Full plate armor, to be practical, would have to be custom built for the wearer. Splints can be made easily, quickly, and in large numbers. Then they can simply be attached to the base armor. Guy is bigger? Simple. Just add a couple more splints. Splint should be far cheaper than plate, while offering a similar level of protection. Just like real life.
Nobody bats an eye in a video game when the farmer says "The raiders are going to burn down my barn and my daughter is in there. Only you can save her! Oh, you're wounded and need healing potions? I have a couple. I'll sell them for 30 gold pieces each." We accept that the world is not going to be believable for the expediency of the game. In one of my campaigns we were recently in a besieged city. They had hundreds of healing potions. And they wouldn't sell them to us at any price. They needed them for their own forces in the upcoming battle. That sucked for us. But it was entirely believable. My character couldn't even buy arrows from them.
Okay. I mean I've only been playing a D&D a year, so I am still learning. But I guess the idea that utility would have little bearing on price seems odd, both in a fantasy world and in the real world. Like demand is a thing, right?
In D&D, demand is not a thing. It is not, nor does it try to be, an economics simulator. If it did, then the price of a suit of plate would be lower in a town closer to the iron mine, and higher in areas where it is harder to get the resource. It would be lower if there were multiple armor smiths nearby, as opposed to one who could charge monopoly prices. And then you also need to factor in regional variance in the cost of living, etc. There are dozens of factors that go into pricing an item. But do we want to spend time calculating those every time we go shopping? Or instead say, plate costs 1,500. I buy some, I put it on, let’s go fight the bandits.
Also, if you want to start down that rabbit hole, just think about that 300gp diamond you need for revivify. What happens if someone discovers a new diamond source and floods the market, lowering prices. Or you just go to an area where diamonds are cheaper for whatever reason. So the diamond you bought 6 months ago for 300 gp is only worth 295 if you were to try to sell it now. Does the spell work anymore?
Its a game, and the costs of items are related to game balance. Trying to impose economics as we understand them on earth, is just a lot of headache for really no payoff.
it's a narrative. Not a video game. You don't need to recalculate anything, and you don't need to simulate anything. No headache needed. Just make something up. It's literally the DMs job.
Demand is absolutely a thing in D&D. Healing potions have a set price. But because of the demands of the siege, we couldn't buy any. The DM ruled they absolutely would not sell to us because of the high demand. He could have also ruled that they would, but only at 500gp per. But, either way, the price and availability were based on demand. If we wanted to buy plate armor off the shelf, he would have said no at any price. They had it. But it was an Orc city. They wouldn't have it in the sizes of our party members. None of our party members were orcs. And they were certainly not going to forge armor for us in the middle of a siege. The forges were busy.
If we were in a city next to an iron mine that was famous for it's output of metal armors, my DM would absolutely rule that plate is cheaper. He would simply make up a price. It would be something less than 1500gp. No math or simulation is needed. It's simply narrative.
The revivify spell works regardless of whether the price you would pay for the diamond changes. The point is that it must be a diamond of a specific size that would normally be worth 300gp. If you get it for 150gp from a seller next to a diamond mine, it would still work. It's still a 300gp diamond regardless of the current market conditions where the buyer is, and regardless of what they buyer paid for it. If you travel to some place where diamonds are extremely rare, a 300gp diamond might cost you 500gp. But it's still a 300gp diamond. You put "300gp diamond" in your inventory. Even if you paid a different price.
Keep in mind when you're comparing the cloak to the armor, the cloak does not give 18 AC. It gives +1 to AC and saves. That's nice, but for anyone not wearing armor already it's not huge. Put a commoner in the cloak and they're still gonna drop pretty fast if anything this side of a housecat attacks them. Somehow give them plate armor AC and they're going to have a lot more breathing room. Thus the cloak has less value because while it can theoretically bridge a gap, it's not doing much work solo. You're not paying 1800 gold for +1 AC. You're paying 1800 gold for a flat 18 AC before other modifiers.
it's a narrative. Not a video game. You don't need to recalculate anything, and you don't need to simulate anything. No headache needed. Just make something up. It's literally the DMs job.
Demand is absolutely a thing in D&D. Healing potions have a set price. But because of the demands of the siege, we couldn't buy any. The DM ruled they absolutely would not sell to us because of the high demand. He could have also ruled that they would, but only at 500gp per. But, either way, the price and availability were based on demand. If we wanted to buy plate armor off the shelf, he would have said no at any price. They had it. But it was an Orc city. They wouldn't have it in the sizes of our party members. None of our party members were orcs. And they were certainly not going to forge armor for us in the middle of a siege. The forges were busy.
If we were in a city next to an iron mine that was famous for it's output of metal armors, my DM would absolutely rule that plate is cheaper. He would simply make up a price. It would be something less than 1500gp. No math or simulation is needed. It's simply narrative.
The revivify spell works regardless of whether the price you would pay for the diamond changes. The point is that it must be a diamond of a specific size that would normally be worth 300gp. If you get it for 150gp from a seller next to a diamond mine, it would still work. It's still a 300gp diamond regardless of the current market conditions where the buyer is, and regardless of what they buyer paid for it. If you travel to some place where diamonds are extremely rare, a 300gp diamond might cost you 500gp. But it's still a 300gp diamond. You put "300gp diamond" in your inventory. Even if you paid a different price.
You are describing house rules, and this is the rules and game mechanics forum. Of course, the DM can make anything cost anything. That's not under debate. But describing your house rules doesn't help answer the OP's question. The issue, particularly in this forum, is the RAW and a possible reason behind it. And the RAW has to do with game balance and does not consider economic factors.
Side note: Nowhere does it say you need a diamond of a certain size, only of a certain GP value. And if you think size is the only factor in determining the price of a diamond or any other gemstone, you are telling me you've never purchased one. And you are making my point. There are many factors which go into the price of everything. And the way we understand those pricing factors is through a modern, developed, capitalist economy. The D&D economy is (depending heavily on the game world) probably pre-industrial, agrarian, mercantilist, infused with magic to some degree, or some combination of those plus more. Just like physics from earth don't work in D&D, economics from earth don't work in D&D. But this being a game, how the economics work doesn't matter. What matters is what it says in the rulebooks. And I've been playing D&D for more than 40 years now. I'm well aware of the difference between it and a video game.
There are drawbacks, albeit minor ones, to using splint armor and a cloak of protection as opposed to just wearing plate armor for 18 AC. The cloak requires attunement, prevents you from wearing another magic cloak, and doesn’t work in an anti-magic field. If AC is a high priority you’re usually better off buying the cloak when you can afford it, assuming your DM allows it to be purchased for its suggested price. But buying plate armor is still the next logical step you’d take to improve your AC after acquiring a cloak of protection, so I don’t see any inherent flaw in their valuation.
it's a narrative. Not a video game. You don't need to recalculate anything, and you don't need to simulate anything. No headache needed. Just make something up. It's literally the DMs job.
Demand is absolutely a thing in D&D. Healing potions have a set price. But because of the demands of the siege, we couldn't buy any. The DM ruled they absolutely would not sell to us because of the high demand. He could have also ruled that they would, but only at 500gp per. But, either way, the price and availability were based on demand. If we wanted to buy plate armor off the shelf, he would have said no at any price. They had it. But it was an Orc city. They wouldn't have it in the sizes of our party members. None of our party members were orcs. And they were certainly not going to forge armor for us in the middle of a siege. The forges were busy.
If we were in a city next to an iron mine that was famous for it's output of metal armors, my DM would absolutely rule that plate is cheaper. He would simply make up a price. It would be something less than 1500gp. No math or simulation is needed. It's simply narrative.
The revivify spell works regardless of whether the price you would pay for the diamond changes. The point is that it must be a diamond of a specific size that would normally be worth 300gp. If you get it for 150gp from a seller next to a diamond mine, it would still work. It's still a 300gp diamond regardless of the current market conditions where the buyer is, and regardless of what they buyer paid for it. If you travel to some place where diamonds are extremely rare, a 300gp diamond might cost you 500gp. But it's still a 300gp diamond. You put "300gp diamond" in your inventory. Even if you paid a different price.
You are describing house rules, and this is the rules and game mechanics forum. Of course, the DM can make anything cost anything. That's not under debate. But describing your house rules doesn't help answer the OP's question. The issue, particularly in this forum, is the RAW and a possible reason behind it. And the RAW has to do with game balance and does not consider economic factors.
Side note: Nowhere does it say you need a diamond of a certain size, only of a certain GP value. And if you think size is the only factor in determining the price of a diamond or any other gemstone, you are telling me you've never purchased one. And you are making my point. There are many factors which go into the price of everything. And the way we understand those pricing factors is through a modern, developed, capitalist economy. The D&D economy is (depending heavily on the game world) probably pre-industrial, agrarian, mercantilist, infused with magic to some degree, or some combination of those plus more. Just like physics from earth don't work in D&D, economics from earth don't work in D&D. But this being a game, how the economics work doesn't matter. What matters is what it says in the rulebooks. And I've been playing D&D for more than 40 years now. I'm well aware of the difference between it and a video game.
The dungeon master's guide says that when determining the availability of things, you should adjust the numbers for special circumstances. The circumstance they use as an example is that healing potions are typically not available in small villages. But a particular small village might have an alchemist. And, if so, they might have healing potions for sale. That's a market condition. It's in the rules, as written. When my DM said that we couldn't get healing potions due to market conditions, he wasn't making a house rule. He wasn't homebrewing. He was applying the rules as they are written.
But if you are determined to go down this path of "all items are priced by game balance," explain to me why the spyglass is priced at 1000gp. Imagine the OP asked, "why is a spyglass so expensive? It's useless compared to a healing potion. And I could get 20 healing potions for that price." How would you answer them?
It's an item that literally has no mechanical effect on the game. It's pure narrative. It's priced that way because of market conditions. The simple answer is that it's rare and difficult to produce. So, for a believable narrative environment, it must be expensive. The market conditions are built into the price. The price of a spyglass has nothing to do with utility or game balance.
Another example is the mace vs the quarterstaff. The quarterstaff is, at the very least, equal to the mace mechanically. The only differences between them is that the quarterstaff is versatile, and it has topple, vs sap as a weapon mastery. They are same damage, damage type, and weight. They are both simple weapons. The mace is the same price as 25 quarterstaffs. Why is the quarterstaff so cheap? It's just a well balanced stick. In the typical market conditions of pretty much any D&D setting, it's going to be trivially easy to obtain one.
So when someone asks why plate armor is so expensive, market conditions is a perfectly valid answer. The prices are set by the devs to create a game environment that "feels" right. Certainly, balance is a thing. But believability is also a thing. If plate armor was 500gp to balance it vs splint, then you would expect to see a whole lot more people walking around in it. And we don't want that. It makes the world less believable. That's why it's insanely expensive. It's supposed to be rare.
And as far as the diamond goes, you can call it size, cut, clarity, or anything else you want. The point remains. The price you paid for the diamond, and the current market conditions for those diamonds, affect the difficulty in obtaining one, and the price you might pay for it. You might not pay for it at all. You might steal it. It doesn't matter. None of these things affect its utility as a material component. That's not a reasonable interpretation of the rules. The reason it's called a 300gp diamond isn't because you must pay that price for it. It's just the name of the item. Mostly, gems are used in D&D as a store of value. They could call it an X carat diamond. But then the DM would need to consult a table when the PC wants to sell one. So they build the typical value into the item name. It's just a lot easier than saying "a diamond stone of princess cut, VS2 clarity, F color, and 1 carat weight or any other diamond of greater value than that."
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So, help me out here. Plate Armor is 1,500gp, for +18 AC. Splint is only 1 less AC for 200gp. That's 1,300 for 1 more AC.
Meanwhile a Cloak of Protection should be 500gp, max, according to the suggested guide? And it gets you +1 to saves as well.
Additionally, heavy armor is much more restricted in who can use it than magic items that grant AC bonuses, so in theory, there should be a discount for the armor. And since a heavy armor wearer can't really increase their AC by raising DEX or another stat like some classes can, often its only choice is to improve armor.
How do people manage prices with situations like this?
I usually don't try to find big reasons behind cost of Equipment or Magic Items, and I tend to follow what the book says. But I'd note that the Dex cap also matters when balancing AC.
For comparison, here's how it was in 3.5e. Not identical, but similar: https://www.d20srd.org/srd/equipment/armor.htm#armorDescriptions
Well, first thing is to not include the cloak in the comparison, as magic items are never guaranteed to be for sale.
But the cost is really a game balance factor. It’s priced so that characters won’t realistically get it before level 3 or 4 (ish). And monster attack bonuses are balanced around hitting certain AC scores at certain points. So you don’t have level 1 or 2 characters running around with an AC 21 (plate + shield + defensive fighting style) so your typical goblin, or kobold or wolf with only a +4 to hit barely has a chance.
I guess I don't understand the question. Price has very little to do with the utility of something. Plate armor is expensive because it's insanely difficult to make using the presumed technology of most DND settings.
A spyglass costs about 1000gp. This is because grinding and polishing glass to precise specifications is difficult. Spyglasses are not terribly useful to adventurers in relation to their cost.
Okay. I mean I've only been playing a D&D a year, so I am still learning. But I guess the idea that utility would have little bearing on price seems odd, both in a fantasy world and in the real world. Like demand is a thing, right?
As for the Cloak comparison, I guess, sure, it not being guaranteed is a thing. Though at the three tables I'm at, the DM does ask the players what items they are looking to purchase. Not all items are made available, but most are. The Cloak is an uncommon item, which from what I've read is intended for tier 1 or 2 levels of play? So I thought it was a fair comparison. As I laid out, with Splint at 200gp, the next jump in armor costs 1,500, but the cloak is at most 1/3 of that and grants you the +1 AC and +1 to all saves to boot. Also, I get non-linear price increases, but the heavy armor prices basically double and then more than septuple from Splint to Plate. Maybe if Plate did something a little more?
Dunno. I just happen to have two level 8/9 characters chilling in Splint Armor, a few hundred gold. So I am of course aiming for the 500gp max Cloak of Protection for both AC & save bonuses, rather than improving my armor. Which is cool. But just feels odd.
Demand is absolutely a thing. Gucci handbags aren't more expensive because they offer more utility compared to a Walmart handbag. In most cases, the Walmart handbag actually offers more utility. More pockets and such. But, like plate armor, Gucci handbags are much more expensive to produce, and much more rare. In the real medieval period, full plate was a luxury item. It was a status symbol. Full plate was almost never worn to battle. That's one of the reasons a lot of plate armor survives to this day. It was simply too expensive to risk damaging it.
I think a lot of people come at roleplaying games from a video game background, where cost of an item is almost always directly related to it's utility. But D&D is a storytelling environment. It's much more important that the environment be believable in a narrative story. Full plate armor, to be practical, would have to be custom built for the wearer. Splints can be made easily, quickly, and in large numbers. Then they can simply be attached to the base armor. Guy is bigger? Simple. Just add a couple more splints. Splint should be far cheaper than plate, while offering a similar level of protection. Just like real life.
Nobody bats an eye in a video game when the farmer says "The raiders are going to burn down my barn and my daughter is in there. Only you can save her! Oh, you're wounded and need healing potions? I have a couple. I'll sell them for 30 gold pieces each." We accept that the world is not going to be believable for the expediency of the game. In one of my campaigns we were recently in a besieged city. They had hundreds of healing potions. And they wouldn't sell them to us at any price. They needed them for their own forces in the upcoming battle. That sucked for us. But it was entirely believable. My character couldn't even buy arrows from them.
In D&D, demand is not a thing. It is not, nor does it try to be, an economics simulator. If it did, then the price of a suit of plate would be lower in a town closer to the iron mine, and higher in areas where it is harder to get the resource. It would be lower if there were multiple armor smiths nearby, as opposed to one who could charge monopoly prices. And then you also need to factor in regional variance in the cost of living, etc. There are dozens of factors that go into pricing an item. But do we want to spend time calculating those every time we go shopping? Or instead say, plate costs 1,500. I buy some, I put it on, let’s go fight the bandits.
Also, if you want to start down that rabbit hole, just think about that 300gp diamond you need for revivify. What happens if someone discovers a new diamond source and floods the market, lowering prices. Or you just go to an area where diamonds are cheaper for whatever reason. So the diamond you bought 6 months ago for 300 gp is only worth 295 if you were to try to sell it now. Does the spell work anymore?
Its a game, and the costs of items are related to game balance. Trying to impose economics as we understand them on earth, is just a lot of headache for really no payoff.
it's a narrative. Not a video game. You don't need to recalculate anything, and you don't need to simulate anything. No headache needed. Just make something up. It's literally the DMs job.
Demand is absolutely a thing in D&D. Healing potions have a set price. But because of the demands of the siege, we couldn't buy any. The DM ruled they absolutely would not sell to us because of the high demand. He could have also ruled that they would, but only at 500gp per. But, either way, the price and availability were based on demand. If we wanted to buy plate armor off the shelf, he would have said no at any price. They had it. But it was an Orc city. They wouldn't have it in the sizes of our party members. None of our party members were orcs. And they were certainly not going to forge armor for us in the middle of a siege. The forges were busy.
If we were in a city next to an iron mine that was famous for it's output of metal armors, my DM would absolutely rule that plate is cheaper. He would simply make up a price. It would be something less than 1500gp. No math or simulation is needed. It's simply narrative.
The revivify spell works regardless of whether the price you would pay for the diamond changes. The point is that it must be a diamond of a specific size that would normally be worth 300gp. If you get it for 150gp from a seller next to a diamond mine, it would still work. It's still a 300gp diamond regardless of the current market conditions where the buyer is, and regardless of what they buyer paid for it. If you travel to some place where diamonds are extremely rare, a 300gp diamond might cost you 500gp. But it's still a 300gp diamond. You put "300gp diamond" in your inventory. Even if you paid a different price.
Keep in mind when you're comparing the cloak to the armor, the cloak does not give 18 AC. It gives +1 to AC and saves. That's nice, but for anyone not wearing armor already it's not huge. Put a commoner in the cloak and they're still gonna drop pretty fast if anything this side of a housecat attacks them. Somehow give them plate armor AC and they're going to have a lot more breathing room. Thus the cloak has less value because while it can theoretically bridge a gap, it's not doing much work solo. You're not paying 1800 gold for +1 AC. You're paying 1800 gold for a flat 18 AC before other modifiers.
You are describing house rules, and this is the rules and game mechanics forum. Of course, the DM can make anything cost anything. That's not under debate. But describing your house rules doesn't help answer the OP's question. The issue, particularly in this forum, is the RAW and a possible reason behind it. And the RAW has to do with game balance and does not consider economic factors.
Side note: Nowhere does it say you need a diamond of a certain size, only of a certain GP value. And if you think size is the only factor in determining the price of a diamond or any other gemstone, you are telling me you've never purchased one. And you are making my point. There are many factors which go into the price of everything. And the way we understand those pricing factors is through a modern, developed, capitalist economy. The D&D economy is (depending heavily on the game world) probably pre-industrial, agrarian, mercantilist, infused with magic to some degree, or some combination of those plus more. Just like physics from earth don't work in D&D, economics from earth don't work in D&D. But this being a game, how the economics work doesn't matter. What matters is what it says in the rulebooks. And I've been playing D&D for more than 40 years now. I'm well aware of the difference between it and a video game.
There are drawbacks, albeit minor ones, to using splint armor and a cloak of protection as opposed to just wearing plate armor for 18 AC. The cloak requires attunement, prevents you from wearing another magic cloak, and doesn’t work in an anti-magic field. If AC is a high priority you’re usually better off buying the cloak when you can afford it, assuming your DM allows it to be purchased for its suggested price. But buying plate armor is still the next logical step you’d take to improve your AC after acquiring a cloak of protection, so I don’t see any inherent flaw in their valuation.
The dungeon master's guide says that when determining the availability of things, you should adjust the numbers for special circumstances. The circumstance they use as an example is that healing potions are typically not available in small villages. But a particular small village might have an alchemist. And, if so, they might have healing potions for sale. That's a market condition. It's in the rules, as written. When my DM said that we couldn't get healing potions due to market conditions, he wasn't making a house rule. He wasn't homebrewing. He was applying the rules as they are written.
But if you are determined to go down this path of "all items are priced by game balance," explain to me why the spyglass is priced at 1000gp. Imagine the OP asked, "why is a spyglass so expensive? It's useless compared to a healing potion. And I could get 20 healing potions for that price." How would you answer them?
It's an item that literally has no mechanical effect on the game. It's pure narrative. It's priced that way because of market conditions. The simple answer is that it's rare and difficult to produce. So, for a believable narrative environment, it must be expensive. The market conditions are built into the price. The price of a spyglass has nothing to do with utility or game balance.
Another example is the mace vs the quarterstaff. The quarterstaff is, at the very least, equal to the mace mechanically. The only differences between them is that the quarterstaff is versatile, and it has topple, vs sap as a weapon mastery. They are same damage, damage type, and weight. They are both simple weapons. The mace is the same price as 25 quarterstaffs. Why is the quarterstaff so cheap? It's just a well balanced stick. In the typical market conditions of pretty much any D&D setting, it's going to be trivially easy to obtain one.
So when someone asks why plate armor is so expensive, market conditions is a perfectly valid answer. The prices are set by the devs to create a game environment that "feels" right. Certainly, balance is a thing. But believability is also a thing. If plate armor was 500gp to balance it vs splint, then you would expect to see a whole lot more people walking around in it. And we don't want that. It makes the world less believable. That's why it's insanely expensive. It's supposed to be rare.
And as far as the diamond goes, you can call it size, cut, clarity, or anything else you want. The point remains. The price you paid for the diamond, and the current market conditions for those diamonds, affect the difficulty in obtaining one, and the price you might pay for it. You might not pay for it at all. You might steal it. It doesn't matter. None of these things affect its utility as a material component. That's not a reasonable interpretation of the rules. The reason it's called a 300gp diamond isn't because you must pay that price for it. It's just the name of the item. Mostly, gems are used in D&D as a store of value. They could call it an X carat diamond. But then the DM would need to consult a table when the PC wants to sell one. So they build the typical value into the item name. It's just a lot easier than saying "a diamond stone of princess cut, VS2 clarity, F color, and 1 carat weight or any other diamond of greater value than that."