[DF 8] On Gemstones and Carats

[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.

[Grouchy Chris]

For comparison, the largest cut diamond in the world is the Golden Jubilee Diamond at 545.67 carats. It had an uncut weight of 755.5 carats.

The largest uncut diamond ever was the Cullinan Diamond, at 3106.75 carats. It was cut into 105 smaller gems.

[Stripe]

Originally Posted by Diomedes

Per Wikipedia, a carat is 200mg, and a diamond's density is 3.5 grams per cubic centimeter. your golf ball comes in at 40.7 cc's, so a diamond that size would weigh 142 grams – 710 carats, about 5 ounces avoirdupois.

Originally Posted by vierasmarius

One carat equals 0.2 grams, so just figure out how much the gemstone weighs and convert to carats. For example, Diamond has a density of around 3.5 grams per cubic centimeter, so a sphere 4.3 cm across (roughly 41.6 cm^3) masses 145 g, hence 725 carats. Clearly, such massive stones are ludicrously rare and valuable; DF8 gives it a price tag of over $21 million.

There's no way I can do that math.

Amethyst has a density of 2.65 g/cm^3. How many carats would a golf-ball-sized one be?

Looks like rubies have the same density as diamonds, so I know that answer.

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.

I centered a whole play-by-post campaign on trying to get rid of a large gem once.

In the end, they sold the priceless, magical gem for something like $1,000 split four ways -- which was a substantial sum less than they agreed to steal it for!

It didn't save them. At least one PC was murdered over it.

[Ulzgoroth]

Originally Posted by Stripe

There's no way I can do that math.

Amethyst has a density of 2.65 g/cm^3. How many carats would a golf-ball-sized one be?

Looks like rubies have the same density as diamonds, so I know that answer.

Diomedes' post included the volume of the golf ball (40.7 cc), which multiplied by the density immediately gives ~108 gram. Or, simply putting "40.7*2.65 gram in carats" into google, you get the conversion to 539.27500 carats.

[Stripe]

Thanks!

....

[vierasmarius]

Originally Posted by Stripe

There's no way I can do that math.

The math itself isn't actually too hard. You just need the formula for a sphere: volume = (4/3) * pi * radius^3. Just plug in the radius in centimeters and it'll give you a volume in cubic centimeters, multiply by density (g/cc) to get grams, then multiply by 5 for carats.

[Peter Knutsen]

Originally Posted by Stripe

There's no way I can do that math.

It's very possible to create a "cheat sheet", using Excel or Calc, for a variety of standard gemstone types and sizes. It's just not something I've gotten around to yet, in part because gemcutting would be anachronistic in my primary setting.

[Bruno]

Originally Posted by Peter Knutsen

It's very possible to create a "cheat sheet", using Excel or Calc, for a variety of standard gemstone types and sizes.

Just made one, specifically aimed at the OP :D It uses the exact rules from DF8, even though they're questionable for semiprecious gems.

Can't use it in GDocs as GDocs does not support drop down boxes and images, so you'll need to download it and open it in Excel to use it;

https://docs.google.com/open?id=0B9v...19sRmJGZzk4STQ

To download go to the GDocs file menu and pick Download. :D

Usage: Click on the orange box next to Gem to pick your gem type from the dropdown list.
Click on the orange box next to Shape to pick the shape of your gem (see the pictures at the bottom of the sheet for examples of everything except Polished Sphere to see what I mean).
Enter the Diameter of your gem and pick your units from the dropdown box (supports Inches and CM)

Sheet gives you volume, weight in ounces, grams, and carats, and gives you the value according to DF8.

I'm working on an alternate to the gems table, splitting it up into precious and semi-precious and calculating the value of each differently. This version has a separate gem quality table, giving you quality ranges from Poor to Flawless (multiplies cost from 1/5x to 5x that indicated by weight).

[cmdicely]

Originally Posted by Bruno

Just made one, specifically aimed at the OP :D It uses the exact rules from DF8, even though they're questionable for semiprecious gems.

Can't use it in GDocs as GDocs does not support drop down boxes and images

Google Docs may not support importing those from Excel, but it definitely supports drop-down boxes and images.

EDIT: Did a quick conversion to a native Google Spreadsheet of the working part of Bruno's spreadsheet (there's more in Bruno's that doesn't connect to the actual calculation part, and that's not included) -- minus the images for now.

[Blind Mapmaker]

That's a neat spreadsheet, Bruno. Many thanks. Makes it much easier to visualize what the gems actually look like for those of us who never deal in carats.