[DF 8] On Gemstones and Carats

[Bruno]

Originally Posted by khorboth

A 1-in-a-million gem is in the 4 biggers range. 6 biggers is probably the only gem of its kind in the world. More than that is just ridiculous.

Nah, you're just looking at the biggest gem in the inner planes, then the biggest gem in the inner and outer planes, and then probably "the heart of the First Dragon/Creator God/Abyss".

On the other side of things, there's "gem stones" as the term is used in jewelery, which is to say "pretty rocks", which can include some that get VERY big.

Quartz: "Well-formed crystals may reach several meters in length and weigh as much as 1,400 pounds (640 kg)."

Jade: "The world's largest pure gemstone quality jade named "Polar Pride" was discovered in British Columbia in the vicinity of Dease Lake. It weighed 18 tones..."

Hematite: "The most spectacular large crystals of hematite--flat plates 6 in. (15 cm) or more across--have been found in metamorphosed Brazilian sediments."

[vierasmarius]

Originally Posted by Bruno

Quartz: "Well-formed crystals may reach several meters in length and weigh as much as 1,400 pounds (640 kg)."

Jade: "The world's largest pure gemstone quality jade named "Polar Pride" was discovered in British Columbia in the vicinity of Dease Lake. It weighed 18 tones..."

Hematite: "The most spectacular large crystals of hematite--flat plates 6 in. (15 cm) or more across--have been found in metamorphosed Brazilian sediments."

For stones that large, I suspect that the Carat-based pricing presented in DF8 breaks down. A single Jade boulder weighing 18 tons (90 million carats) would be valued at $162 Quadrillion, which is over 2500 times the GDP of the entire planet. Even a 1400 pound quartz comes in at over $150 Trillion. At some point the pricing scheme must drop the mass^2 component, and plateau at a fixed price per kilo.

[dcarson]

There is a cave in Mexico with impressive gypsum crystals.

[Bruno]

Originally Posted by vierasmarius

At some point the pricing scheme must drop the mass^2 component, and plateau at a fixed price per kilo.

It currently doesn't, despite having a whole bunch of decorative stones and not-really-stone materials that appear in single pieces significantly larger than traditional "gemstones".

Which is probably a decent enough abstraction for DF - it's not like the value per carat isn't completely made up as it is. But quartz, jade, jet, coral, etc and any of the bulk iron or copper ores should (in a more accuracy-concerned game) just be a fixed per pound measurement (SJG measures by the lb, as much as I'd prefer kg).

My point was more "Or the giant stone in the idols eye could be Chalcondy" - still seriously worth it as a giant lump of reasonably expensive decorative material, but not quite so economy imploding as a giant ruby.

[Anthony]

The based on square of carats is largely a function of the rarity of large unflawed stone. For stones where flaws are invisible or irrelevant, it doesn't make sense.

[Peter Knutsen]

Originally Posted by Bruno

It currently doesn't, despite having a whole bunch of decorative stones and not-really-stone materials that appear in single pieces significantly larger than traditional "gemstones".

Which is probably a decent enough abstraction for DF - it's not like the value per carat isn't completely made up as it is. But quartz, jade, jet, coral, etc and any of the bulk iron or copper ores should (in a more accuracy-concerned game) just be a fixed per pound measurement (SJG measures by the lb, as much as I'd prefer kg).

There was an article in Pyramid v2, about the value of precious and semi-precious gemstones. For precious gemstones, the carat weight was lifted to the 2nd power, possible with a linear component too (IIRC similar to the Powerstone rules for 3E and/or 4E), and that seemed sensible to me.

For semi-precious stones and materials, such as amber, the rule was that you lfited the carat weight to the power of 1.01. That seemed kinda sensible to me, since it seems to me that one lump of amber weighing 50 grams should be worth somewhat more than two lumps of amber each at 25 grams.

But then I tried the formula with some actual numbers, and it turns out that a 1 kilogram semi-precious stone (5000 carats) is only worth about 10% more than the same mass distributed amoung thousands of smaller stones (weighting 1-2 carats each).

So if you use that formula, it's not worth the bother. I do maintain that larger lumps of amber should be worth somewhat disproportionately more, but I haven't needed to solve the problem yet, so I don't know what kind of power to use, 1.05 or 1.1, to produce results that seem reasonable. Or that are even worth the bother. The Pyramid formula seems like a waste of time, performing an arithmetical calculation - even if it is a very simple one - for really no gain at all.

[schmeelke]

Originally Posted by Bruno

Quartz: "Well-formed crystals may reach several meters in length and weigh as much as 1,400 pounds (640 kg)."

^
~3.2 million carats! Worth ~$150 trillion according to DF8.

Not only is this one a powerstone, but it's enchanted as well. Even the shard in his hand is pretty big for a powerstone.

[Captain-Captain]

Of course DF gems are likely measured in ounces. if not pounds...

[Kax]

Originally Posted by Refplace

As the price was already answered one thing to consider if you really want that size without bank rolling the PCs for life.
That is more then a Kings ransom and likely searching for a buyer would be a significant adventure on its own. Its perfectly reasonable to say no buyer exists in fact. They may chop it down to smaller pieces but would lose a lot of the value and still may have troubles.

So give them a 710 carat zircon. :)