Real-life Gemstone size ranges

[Fiery Diamond]

So, because the prices given for various gems in the treasure chart in 3.5 are outlandish, I decided to modify them somewhat based on relative size: "shards" are 10% list price, "small" are 30%, "medium" are 60%, and "large" are 100%. (with the potential for there being even larger sizes for certain kinds of stones, but probably not all)

But those are relative sizes. For most of the more valuable stones, "shard" can fairly easily be defined as "the size you'd stick in a ring without being super ostentatious." After that, though...problems arise. Different gems would have different maximum sizes, after all, and would have different expected minimums. I mean, I wouldn't expect my standard garnet to be the same size as my standard piece of obsidian.

I know that in many games (and stories) this is sort of handwaved away as "gems can be as big as we feel like, and crazy prices just mean you have a fist-sized emerald," but I'd rather not just do that. I'd like some sort of consistency... It might be realistic to find a two foot diameter chunk of obsidian near a volcano, but I don't want to meet that baseline by having a two foot diameter chunk of diamond...I'd feel silly.

I was just going to search the internet, but my searching skills are failing me. So, I come to you people: Help me figure out what sort of size ranges various gems would have, especially the gems listed in D&D books.

(Also, for a campaign, I'm going to have a society that did away with using gold as currency (magical society, has divided intrinsic value as determined by spells and magic item creation and economic value into two mostly unrelated things) and makes gemstone coinage...knowing how big a gem could realistically get could effect what gems they could turn into coins, too.)

[Togath]

I know Quartz crystals are usually fairly large, with a few minutes of searching(just walking along watching for Quartz) a beach you can usually find a crystal of Quartz about 3-4 inches in diameter, so I would imagine that Quartz crystals used as coins would either be fairly large, with about standard value, or smaller, and of little value. Rose Quartz, aventurine, Tiger's Eye, Jasper, Agate, and Amethyst are differently colored forms of quartz and usually considered more valuable, though in nature they often occur in similar sized crystals to those of standard quartz, though Agate and Amethyst are slightly smaller than standard quartz if I remember correctly., just looked it up amethyst is usually much smaller then plain milky/white quartz, while agate is usually found in bands rather than free standing crystals
edit #2; tiger's eye, jasper, and aventurine are also usually found as mineral bands rather than in crystal from.

[WildPyre]

I've always wondered how people keep from haggling terribly over how much a gem is worth. I've played around a bit with the idea of the local government banding and stamping prices on sizable gems for them to be used as currency, but then I worry about things like counterfitting and the such... even though the group I normally play with is highly unlikely to pull such shenanigans.

[Winter_Wolf]

I know that in many games (and stories) this is sort of handwaved away as "gems can be as big as we feel like, and crazy prices just mean you have a fist-sized emerald," but I'd rather not just do that. I'd like some sort of consistency... It might be realistic to find a two foot diameter chunk of obsidian near a volcano, but I don't want to meet that baseline by having a two foot diameter chunk of diamond...I'd feel silly.


Many games, and stories, and in real life, that's pretty much how valuation of gemstones actually works. (By hand-waving and guesstimation I mean, not by having 2 foot chunks of diamond lying around.)

Okay, not really. But in a sense, people just make up prices for gems and gemstones in the real world.

An example of a crazy expensive diamond would be the Hope Diamond (http://en.wikipedia.org/wiki/Hope_Diamond) is 45.52 carats (9.10g), estimated at $200 million to $250 million US dollars (but I'm sure that includes the other diamonds too), and is somewhat less than 1" cubed.

A 1.0-2.0 carat (quality) cut diamond can be had for $10,000-15,000 US dollars, and is about 5/32" in diameter.

You can buy a 2" (50mm) sphere of black obsidian on Amazon.com for $25 USD.

Those are worked stone prices. In the raw, prices would be significantly less. A tiny chip of diamond is probably practically worthless, since I imagine it can't be worked into anything and looks like shiny glass.

[Cieyrin]

You could take a page from Exalted, who use slabs of Jade as their currency in most of the civilized areas. Jade is far more available in the setting and has intrinsic value to the powerful people around, since it meshes well with their powers, so they just carve the Jade into bars and coins and lower denominations are just further broken down from there.

[leakingpen]

Value isn't just based on size. Certain colors mean purer gemstones, and or are more pretty. Clarity is a big issue, how perfectly clear a stone is. cut also influences price, but im not sure if d and d states precut price for spell component use or not. but the same diamond, cut three different ways, can be worth 100, 1000, or 10000 dollars.

[Dimers]

A magic-heavy society should certainly be able to use spells to merge together similar gemstones, purify stones over time, cut and polish beautifully, and so forth. Spells could also determine precise weight and verify whether a stone is real or just a look-alike. So setting aside the problems of counterfeiting-oriented magic, it's reasonable to have large and perfect gems used as high-value currency of known objective value.

[Yora]

Value isn't just based on size. Certain colors mean purer gemstones, and or are more pretty. Clarity is a big issue, how perfectly clear a stone is. cut also influences price, but im not sure if d and d states precut price for spell component use or not. but the same diamond, cut three different ways, can be worth 100, 1000, or 10000 dollars.
Then there's also collectors value. If a specific gem becomes famous, people will be willing to pay a lot more for it than for another stone of the same size and shape.

[Fhaolan]

Value isn't just based on size. Certain colors mean purer gemstones, and or are more pretty. Clarity is a big issue, how perfectly clear a stone is. cut also influences price, but im not sure if d and d states precut price for spell component use or not. but the same diamond, cut three different ways, can be worth 100, 1000, or 10000 dollars.

There is also inclusions, where other materials show up inside the gem. For many types of gem this is normally considered a defect (like diamonds), but occasionally the inclusion becomes part of the desired effect and will increase the value of the stone (the star in star saphires for example.)

[Kneenibble]

You could have three sapphires side by side, each the size of your thumbnail.

The first one is grayish-blue, not tranlucent, and filled with visible inclusions that distort its clarity. It is quite big, though, so it's not entirely valueless.

The second one is a midnight blue that is tranlucent but too dark to see through clearly. It is very shiny, and there are only very small inclusions: all the same you have to hold it up to the sun to see much light coming through it at all. It is quite big, though, and its value is fairly high for that.

The third one is a rich azure blue, perfectly clear and translucent, without any visible inclusions -- indeed, under the microscope, none at all. It is shiny and breathtaking. At this size and quality, its value is inestimable.

Most gems worth their salt are measured in millimetres. You can get pretty big chunks of opaque veiny corundum, even cut as gems, but they're basically colourful rocks and worth as much. A thumbnail sized precious stone of any remarkable quality is incredibly rare and in the six figure zone at the least.

Every gem has these extremes in value based on colour, clarity, and as mentioned, cut, in addition to size (and size, in relation to the other three, exponentially scales the value). That would be the trouble with attempting to mimic a standardized currency based on gems, unless the government has the ability to synthesize them -- synthesized gems can be perfect and identical. - or, unless you used something as common and not so varying in quality as quartz, but then you're doing a fiat currency.

[Wardog]

I've played around a bit with the idea of the local government banding and stamping prices on sizable gems for them to be used as currency

I would think gems are too variable in size and quality to make good currency, even if they were common enough to be useable as such.

If I break a gold coin in half, I still have the same weight of gold, which will most likely still have the same value, and can be melted down and recycled to make something else (including a new coin, if you have the authority and/or forgery skills).

If I break a diamond, I may end up with near-worthless fragments. If I skillfully cut it instead, I may end up with something more valuable.



A magic-heavy society should certainly be able to use spells to merge together similar gemstones, purify stones over time, cut and polish beautifully, and so forth. Spells could also determine precise weight and verify whether a stone is real or just a look-alike. So setting aside the problems of counterfeiting-oriented magic, it's reasonable to have large and perfect gems used as high-value currency of known objective value.

We currently have the technology to make gem-quality diamonds that are just as good as natural ones. They sell for much less, because people don't consider them to be "real" and won't pay as much for them.

(Of course, that may just be a quirk of our culture. A fantasy culture need not have the same aversion to manufactured gems. The Noldor didn't after all).

[WildPyre]

I would think gems are too variable in size and quality to make good currency, even if they were common enough to be useable as such.

If I break a gold coin in half, I still have the same weight of gold, which will most likely still have the same value, and can be melted down and recycled to make something else (including a new coin, if you have the authority and/or forgery skills).



Yeah the actual idea was more along the lines of people having their gemstones "certified" by the local ruling party so there wouldn't be any haggling or confusion over the price, more so than using them as currency. I just described it poorly.

[sdream]

The ridiculous values of diamonds are not a cultural "quirk" but ruthless marketing on the part of the companies that have diamond mining banana republics in their pocket. Look debeers and blood diamonds.

As for using currency involving metals and gems, I prefer to imagine that in a functional fantasy world alchemy is involved.

Copper, tin, and other base metals are common and somewhat useful, if only because alchemy can reversably condense them into:

Cold Iron and Silver, the first rank precious metals, with the ability to penetrate some kinds of magical defenses, which in turn can be reversably condensed into:

Gold - not terribly difficult to manufacture, or convert to lesser metals, but with great skill Gold can be reversably alchemically condensed into:

Adamantine and Mithril - the top precious metals, which require large amounts of gold to create, but have very powerful proporties and are very tough. Not quite as hard, but more durable than what they can be turned into:

Gemstones - all gemstones are diamond of varying colors, and can be tested simply for purity as they glow when power is poured into them ALA use magic device (untrained). Alchemists can trivially meld, color, or shape diamond, but it is to valuable and fragile for most weapons. It is used in many spells in certain sizes and can be condensed further into:

Spellstones - your pearls of power, absorbing background magical radiation and able to be tapped by spellcasters for this power.

The relative value of materials is maintained by the physical laws that allow alchemists to transmute one into another, which is as convenient for ironworkers as it is for adventurers.

[leakingpen]

Then there's also collectors value. If a specific gem becomes famous, people will be willing to pay a lot more for it than for another stone of the same size and shape.

Well, yeah, but I was referring to value for purpose of spell casting components. I highly doubt a GM would let you factor in fame for that purpose (cause, well, using such a gem, that better be an EPIC spell. )

[Analytica]

The ridiculous values of diamonds are not a cultural "quirk" but ruthless marketing on the part of the companies that have diamond mining banana republics in their pocket. Look debeers and blood diamonds.

As for using currency involving metals and gems, I prefer to imagine that in a functional fantasy world alchemy is involved.

Copper, tin, and other base metals are common and somewhat useful, if only because alchemy can reversably condense them into:

Cold Iron and Silver, the first rank precious metals, with the ability to penetrate some kinds of magical defenses, which in turn can be reversably condensed into:

Gold - not terribly difficult to manufacture, or convert to lesser metals, but with great skill Gold can be reversably alchemically condensed into:

Adamantine and Mithril - the top precious metals, which require large amounts of gold to create, but have very powerful proporties and are very tough. Not quite as hard, but more durable than what they can be turned into:

Gemstones - all gemstones are diamond of varying colors, and can be tested simply for purity as they glow when power is poured into them ALA use magic device (untrained). Alchemists can trivially meld, color, or shape diamond, but it is to valuable and fragile for most weapons. It is used in many spells in certain sizes and can be condensed further into:

Spellstones - your pearls of power, absorbing background magical radiation and able to be tapped by spellcasters for this power.

The relative value of materials is maintained by the physical laws that allow alchemists to transmute one into another, which is as convenient for ironworkers as it is for adventurers.

I want to play in your game. This just screams "logically coherent magical metaphysics and fantasy world". :smallbiggrin:

[bokodasu]

If you're willing to drop a couple of bucks (literally, I think I paid $.75 for it in a sale), go to rpgnow.com and pick up a copy of Faster Monkey Games' "All the Treasures of the World: Part I: Gems". I love it. It covers all the stuff covered above - how size, inclusions, quality, rarity, etc. affect prices, and even has a chart on how real-world gem sizes map to fantasy gem sizes. It's a really nice little resource. (Part II is Jewels, if you want to randomly generate some pretty treasures; go ahead and pick it up while you're there, it's fun too.)

[Dragonmuncher]

Has anyone read Way of Kings, by Brandon Sanderson?

His world uses a currency of gemstones. They're encased in very tough glass spheres, and due to a quirk in the magic system "absorb" light during thunderstorms, and then emit light as a candle or lantern would for the next week or so.

By law, lit and unlit stones are worth the same amount, though obviously lit have some practical value.


http://stormlightarchive.wikia.com/wiki/Currency