Volume of Gems

[Ruethgar]

While many objects can be calculated with rough real world estimates, I find myself needing the info for gems in particular for a half dragon’s body pouch. So is there anywhere that says what the size and gold ratio of gems are? Or is it pretty much up to the table to define and say ‘oh this pea sized diamond is perfect quality 5k but the fist sized one is cloudy and flawed 1k.’

Any source is acceptable, though official 3.5 or PF is preferable.

Edit: For now using the 5e 1/4in diameter but would still prefer 3.5/PF1

[unseenmage]

Arms and Equipment Guide has some info on gems and jewelry and such. Basically it has the value it has and is as small as it needs to be IIRC.

[Ruethgar]

I see the cost for jewelry specifically without gems, but nothing about gems themselves. They also mention gems on a few items and the hireling gemcutter. Is there a specific page?

Edit: Going with the 5e gem size and 3e bag volumes makes them practically negligible. 50 easily in a cubic inch with DMG pricing them in the thousands is pretty efficient use of space.

[Biggus]

First diamond I found for sale on Google is about 9mm (1/3 of an inch) in diameter, weighs 0.52g (0.02oz) and costs £10,250 ($13,325).

At a rough estimate I'd say that equates to 50GP. If so, 1lb of those diamonds would be worth about 40,000GP.

So for high-quality gems, weight is going to be negligible unless you have a king's ransom in them. Lower-quality gems may have some noticable weight.

[Ruethgar]

Yeah, he’s going to favor green gems. Jade can get pretty damn big. Currently have his starting gold split into 1/2” 1g malachite/moss agate/turquoise/lapis gems made by the gem blast spell side effect, and a 3x1.5x1.5” hunk of jade to cover a few platinum with tarnished copper coins for the lower currency.

[Arael666]

First diamond I found for sale on Google is about 9mm (1/3 of an inch) in diameter, weighs 0.52g (0.02oz) and costs £10,250 ($13,325).

At a rough estimate I'd say that equates to 50GP. If so, 1lb of those diamonds would be worth about 40,000GP.

So for high-quality gems, weight is going to be negligible unless you have a king's ransom in them. Lower-quality gems may have some noticable weight.

In the real world, gemstones have various factors that influence their price, such as variety, color, clarity, size, if it was cut and the shape of the cut. In D&D, gemstones have always been vagely described, which is, in my humble opinion, the devs saying "a gem is as big as you want them to be and costs however much you want them to cost". I know the playground has the tendency to overanalise everything, but I don't really think this needs to be scrutinized at all.

[Vaern]

I think gems are assumed to be valued based on quality and clarity and whatnot rather than volume. You could potentially have a single gemstone the size of your pinky nail of such high quality that it's worth the entire fortune of an epic level character, useful for circumventing the fact that at a certain point your mountain of gold will have roughly the same mass as the sun.

[Zanos]

I think they'd have to be based largely on cut and quality, since there are gems used as spell components that would be massive if it were volume alone. I seriously doubt the Onyx gem you need to raise a 20HD skeleton is 20 times the size of the ones used to raise a 1HD skeleton, for example.

And of course there are real examples of gems worth ludicrous amounts. The Hope Diamond is worth hundreds of millions and weighs 9 grams.

[hamishspence]

If regular skeletons got 1 carat stones and 20HD skeletons got 20 carat stones - they still wouldn't be super-huge. 20 carats is about the upper limit of what can be worn on a ring.

[Particle_Man]

Trouble is realism says that most gems are light and tiny but fantasy art and fantasy tales often have rubies, emeralds, sapphires and diamonds as big as Conan’s fists, nestled among unrealistic gold coins that looks like half-sized hockey pucks.

So the answer would be (at least partly) which end of that spectrum best fits your game?

[Arael666]

Trouble is realism says that most gems are light and tiny but fantasy art and fantasy tales often have rubies, emeralds, sapphires and diamonds as big as Conan’s fists, nestled among unrealistic gold coins that looks like half-sized hockey pucks.

So the answer would be (at least partly) which end of that spectrum best fits your game?

Lets be fair, most of those oversized gems are MacGuffins

[tyckspoon]

Trouble is realism says that most gems are light and tiny but fantasy art and fantasy tales often have rubies, emeralds, sapphires and diamonds as big as Conan’s fists, nestled among unrealistic gold coins that looks like half-sized hockey pucks.


It's so you can have dragons sleep on their hoards and demons and things tower over them imposingly; if you don't have impossibly large gems and coins, then in order for a treasure hoard to actually *look* large it has to have a truly staggering amount of value in it.

..also probably that drawing a couple tens of thousands of very large coins and gems is obnoxious enough for an illustrator, nobody would put up with being asked to draw several million realistically sized coins and you wouldn't even be able to pick out the gems.

[farothel]

If you want some more information, I found this (https://dungeonsdragons.fandom.com/wiki/Gemstone) online. It can offer a starting point.

EDIT: or this (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/dungeon-masters-only/60756-gem-prices), which has weights in it.

[Yahzi Coyote]

From Merchants of Prime (https://www.drivethrurpg.com/product/218456/Merchants-of-Prime):



Gems


Gem
Color
Cost / carat


Jacinth
Orange
10 gp


Onyx
Black
25 gp


Ruby
Red
200 gp


Topaz
Yellow
50 gp


Emerald
Green
250 gp


Sapphire
Blue
150 gp


Pearl
White
1 gp


Amethyst
Purple
100 gp


Diamond
Clear
500 gp



A “standard” gem, round and faceted like a typical diamond ring, is ¼ inch in diameter and weighs 1 carat; a gem ½ inch across (the size of a marble) is about 10 carats; a 1 inch gem (like a false eye) is about 75 carats. Double those weights for a gem that is a sphere, instead of standard cut. A 2 inch spherical gem (big enough to use as a pool table ball) weighs ½ lb; one large enough to carve a skull out of is 15 lb (or 36,000 carats). Standardized modern pearls are about 3 carats.

There are 3.125 coins to the ounce if it should matter; and about 150 carats to the ounce. On Earth gems become exponentially more valuable the larger they are; on Prime, where gems are often used as fuel for magic and imported from other planes, this complication can usually be ignored. Creative and repeated use of the Make Whole spell could arguably meld many small gems into a single large one, which explains where Necromancers get all those crystal skulls.