I’m the kind of reader who can get caught up on the details. One of the delightful and delicious things about fantasy and science fiction is the freedom authors have to craft crazy worlds and play with speculative concepts. But I also expect these worlds to have internal integrity – in other words, I want it all to make sense. So when an author tells me salt is a luxury and people live on the very basics in a medieval village far from any trading routes, I find myself wondering why the village windows are made of glass. Devil in the details.
A couple days ago, author @ilona_andrews posted a tweet about something most writers encounter at least half-a-dozen times when writing a book: “What would this cool idea really mean for my fantasy world?”
In this case, the question was about the weight of a pelt of gold:
I was curious too, but the numbers I first kept getting seemed just too high (over 200 pounds of gold? Surely not.) and different every time as I kept tweaking my formulas and reinterpreting what “surface area” really meant. My housemate saw me scribbling rows of numbers in the margins of a grading rubric, and asked me what I was doing:
“I’m calculating the weight of a fur pelt made of gold. Assuming each hair is 6 inches and there are 12 per millimeter…”
“Is it an assignment?”
“Nope. Someone tweeted the question.”
“Someone you know?”
“Why do they wanna know?”
But half an hour of mini-scribbles, nose-scratching, and strange results later, I gave in. Google would save me. I told it to fetch me an answer I could use a baseline for comparison. And I knew just how to do it:
“How much would the golden fleece weigh?”
“Golden fleece weight”
“Gold fleece weight or else”
Nothing. Jason stole the golden thing over twenty nine centuries ago. That should have been plenty of time for someone to do the math and schedule the answer forward as a blog post. But Google was stubbornly unhelpful and the internet singularly un-forthcoming.
The next morning, over lunch, I found myself doodling my way through the problem – and enjoying myself way too much.
I realized it was time to get down to business.
So how much would a golden fleece weigh?
Here are a few assumptions and givens:
- Each fur follicle is solid gold. Yep, you probably don’t want to curl up on this throw rug.
- I did the calculations with skin and without. Maybe the pelt got touched by Midas, or maybe it’s just the fur. Let’s explore both options.
- For number of hairs per surface area, I’m using an average between male and female sheep, not merely ram. And generally, I’m assuming ram = sheep and leaving it at that.
- According to a conveniently on-hand and google-able online store, a sheep rug is about 2.5 feet by 3.3 feet. Gonna run with that. That’s 7,665.7 cm sq.
- After entirely too much time reading articles with titles like “Determination of wool follicle characteristics of Iranian sheep breeds,” I’m going to go with 16 hair follicles per millimeter.
- Found a chart listing average hair shaft diameters across a dozen species (from 25 micron diameter for dogs to 160 for cows, huh). Sheep came in at 90 microns.
- Assuming it’s super-pure (since it’s gonna be organic, after all), a cubic centimeter comes in at 19.32 grams of gold.
Where does that leave me? Well, assuming the skin is organic, a sheep wearing 6-inch-long fur would be carrying a load of 48 pounds on itself. If the fur is closer to the average 2.5 inches, then we’re looking at 20 pounds of gold fur. At current rates, the little guy’s fur would be worth about $500,000. Still, it begs the question about how you’d go about the shearing side of things (that’s a question for later).
Now if you’re gonna go with the King Midas Touched That Sheep Theory, let’s assume the skin is solid gold too. I have no idea how thick sheep skin is, and while I found out that hippo skin can be 2 inches thick and leather comes in a great range, the internet wasn’t very helpful when it comes to sheep. So I eyeballed it. Two millimeters look about right.
One Length-times-Width-times-Height-formula later, I had the volume of the skin part of the pelt. Multiply it by grams per cubic centimeters, convert it to pounds, and we have our gold sheep skin, coming in at 62 pounds of gold, with a total weight of either 110 pounds for our long-wool sheep and 82 pounds for the sheep with the average 2.5 fur.
Conclusion – The Weight of a Golden Pelt
And there it is. It seems like a lot, but a sheep can weight anywhere from 90 to 300 pounds, so a 300-pound winged ram could probably wear 20 pounds of fur without toppling over (whether it would fall out of the air is a whole ‘nother question). And if both the pelt and skin were solid gold, Jason is just a bit more impressive, sneaking that heavy thing off from under the nose of the dragon.
CORRECTION UPDATE: There was an error in one of my conversions. Having fixed it, the number of the 6-inch fur for a sheep would be 50lbs, and 21lbs with 2.5 inch-long fur. If the numbers of hair per sq mm is adjusted up to 55 (instead of 16) and all else is held constant, then the weight of the 6-inch fur pelt goes up to 174lbs (??? surely not?) (without gold skin).