Prices for precious stones

[alphabetagamadelta]

Is there any standard price for 1g of each precious stone? I want to have some base when making treasures. Game is a fantasy world with TL3 and normal mana.

[Pursuivant]

Originally Posted by alphabetagamadelta

Is there any standard price for 1g of each precious stone? I want to have some base when making treasures. Game is a fantasy world with TL3 and normal mana.

No. Low Tech and DF Treasure Tables sort of get into this area, but they don't provide specific prices for a given type of stone. Historically, different cultures valued different stones and prices could vary widely. The Low Tech rules for Luxury Pricing definitely apply.

Modern prices depend as much on cut, quality, marketing, and artificial scarcity as size.

[Anthony]

Originally Posted by alphabetagamadelta

Is there any standard price for 1g of each precious stone? I want to have some base when making treasures. Game is a fantasy world with TL3 and normal mana.

The weight of gems is pretty much irrelevant unless the total volume is so high that it's going to crash the market anyway -- one gram is five carats -- or your 'gems' are things like clear quartz. I would just ignore carat weights and say "$X in gemstones".

[malloyd]

Originally Posted by Anthony

I would just ignore carat weights and say "$X in gemstones".

Note that you probably should also usually ignore what kind of stones the gems are. The problem with a per gram price by type of gemstone is that is makes the historically doubtful assumption that any substantial fraction of potential buyers and sellers have any idea at all what the type even is. Most gems sell as art, not materials. They get priced by how pretty the happen to look vs the other available choices, and/or the coolness of the story attached to them, not their chemical composition.

[RGTraynor]

The prices are also highly variable: a classic example is amethyst, which ranked in value right up there with rubies and emeralds until large South American deposits were discovered, at which point the price cratered.

Honestly, you can just establish a fiat, if you want. I agree that your players will probably not care about the precise differences between sapphire+pearl+zircon+citrine+etc. But if they do, Dungeon Fantasy 8 actually does go into gem prices. (The numbers are pretty screwed up -- diamonds are only eight times as valuable as HEMATITE?? -- but eh.)

And if you don't like the numbers, eh, just change them: if you decide that opal is more valuable than diamonds in your setting, then it is!

[Aldric]

Originally Posted by RGTraynor

And if you don't like the numbers, eh, just change them: if you decide that opal is more valuable than diamonds in your setting, then it is!

Depending on what kind of spells use what gems as material, or what enchantments work on which gems, that may very well happen.

[The Colonel]

Concur with the "cultural" note - the primacy of diamonds is very recent, rubies used to be the most expensive stone historically (although "rubies" could include a variety of clear red gemstones, including garnets and spinels (sometimes known as "balas rubies" when they could be distinguished from the real thing. Conversely a non-red ruby was typically called a sapphire or identified as something else.

Greco-Roman culture was also highly fixated on pearls.

Cultural value will also depend on tolerance for flaws and imperfections - some flaws, like asterism, greatly enhance the value of a ruby, others reduce it ... unless you have a culture which values these sorts of oddities. Likewise, discoloured or misshapen pearls could be worthless trash or precious curios.

Most RPGs treat glass or rock crystal jewellery as trash - but for an early medieval setting, glass was rare, hard to work and acceptable as a jewellery material (Romano-British and Saxon work sometimes shows up decorated with pieces of Roman glass apparently re-worked from scrap) ... and rock crystal could be cut and faced by cultures that struggled with anything harder (again, in medieval Europe, diamond was considered un-cuttable in many times and places and even softer stones could find themselves cabochoned and polished rather than cut).

Also, in the real world, a gemstone bigger than a man's thumbnail is a monster - the Hope Diamond and the Koh-I-Noor are both about the size of a queen olive and they are famous giants amongst finished stones with a market value that is hard to assess, let alone realise. Fantasy gemstones regularly reach or exceed this size without causing undue disturbance ... but it would be amusing to allow PCs to steal a monster that they cannot then sell because no-one can afford to give them more than a fraction of the market value.

[Varyon]

Originally Posted by RGTraynor

(The numbers are pretty screwed up -- diamonds are only eight times as valuable as HEMATITE?? -- but eh.)

De Beers doesn't exist in most DF settings.

[ravenfish]

Originally Posted by The Colonel

Conversely a non-red ruby was typically called a sapphire or identified as something else.

Isn't a non-red ruby still called a sapphire? My understanding is that a ruby, by (modern) definition, is red gem-quality corundum, and a sapphire is non-red gem-quality corundum.

[Varyon]

Originally Posted by alphabetagamadelta

Is there any standard price for 1g of each precious stone? I want to have some base when making treasures. Game is a fantasy world with TL3 and normal mana.

As noted, DF8 has you covered, here. Roughly speaking, the value of a gem scales with the square of its weight, typically measured in carats - so rather than a 1 carat stone being worth twice as much as a 0.5 carat one, it's closer to 4x as much. You then multiply this by some value depending on what the gem actually is, ranging from 2 (obsidian) to 40 (diamond). Of course, I said roughly because it's actually a quadratic equation that I'm not comfortable plagiarizing here (in fact, with the above example, it actually works out being closer to 2x than 4x).

Naturally, there are other aspects that can boost or reduce the worth of a gem, given the above only handles one of the "3 C's," carats (leaving out color and cut). For DF purposes, size is typically all that matters, but if you want to have distinctions (like Diablo II's Chipped->Flawed->Regular->Flawless->Perfect progression, say), I'd probably have them just modify the value multiplier. Perhaps a highly-flawed gem is 1/5x price, a moderately-flawed one is 1/2x, a near-flawless one is 2x, and a perfect one is 5x, for example.