And they say they were aiming for a conservative minimum. Sheesh, I've never found that much in a dragon hoard. Where'd he even get all that? Stealing all that must have revalued all prices in Middle Earth.
Actually, several posters comment on his article to note that he grossly underestimated Smaug's size. Poster geniesolmyr plugged in the corrected values to get a much more accurate number. Inspired, I did the same. Let's walk through the steps from the original article with the corrected size values and see what we get.
Smaug's hoard is calculated in three parts: the coins he sleeps on, the diamonds embedded in his body, and the Arkenstone of Thrain gemstone.
Smaug is noted as being a "red-golden color" in
The Hobbit, and we'll assume that he's of colossal size due to his advanced age. Now the 3.5
Draconomicon notes the body sizes (from the shoulders to the base of the tail) of a colossal gold dragon as being 33 ft. long and 15 ft. wide. By contrast, a colossal red dragon is 35 ft. long and 15 ft. wide. Since we can't say for certain whether Smaug was a red dragon or a gold dragon who went bad (or, like in Eberron, the dragons don't have alignment determined by color), we'll average the measurements. Hence, Smaug's body is 34 ft. long and 15 ft. wide.
Assuming Smaug curls up on his hoard, we'll assume it has a diameter equal to his body length (34 ft.). Since Frodo, who is about 3 ft. tall, had to climb over the hoard, let's assume the hoard is twice his height, or about 6 ft. tall, and then add one extra foot for how Smaug's great weight was compressing it. So the hoard is 7 ft. tall altogether.
To keep it simple, we'll assume Smaug's hoard is a cone. The volume of cone that has a 17 ft. radius and 7 ft. height is (after rounding everything past the second decimal point) 2,118.5 cubic feet.
Now, we'll reduce this by 30% to account for miscellaneous objects in the hoard, such as air pockets, dead bodies from would-be thieves, and various objets d'art. This gives us 1,483 cubic feet of nothing but coins.
Since, as the article notes, Bilbo takes two chests of coins, one of silver and the other gold, we'll assume the hoard is 50% gold coins and 50% silver coins. That's 741.5 cubic feet of each.
The article then gives us the measurements for individual gold and silver coins:
A Kuggerrand, the South African Coin containing 1 troy ounce of pure gold, measures 32.6 mm in diameter and is 2.84 mm thick. Solving for the volume of a cylinder( V= pi r(squared) h), then converting cubic millimeters to cubic inches, then cubic inches to cubic feet gives a volume of 8.371354e-05 (or 0.00008371354) square feet for a single coin, containing one ounce of gold.
Using similar logic, an American Silver Eagle coin (40.6 mm in diameter, 2.98 mm thick), which contains one troy ounce of silver, has a volume of 0.000136 square feet.
This lets us calculate that there are 8.9 million gold coins and 5.5 million silver coins, presuming they were all one (troy) ounce coins.
Again, the article then gives us the value of an ounce of gold and silver:
At the moment gold is trading at $1423.8/ounce and silver at $37.5/ounce
From this, we calculate a grand total of $12,671,820,000 USD in gold coins, $206,250,000 USD in silver coins. Hence, the total coin value of Smaug's hoard is $12,878,070,000 USD. We'll round that down to
$12,878,000,000 USD.
Now, on to the diamonds.
Presuming the body proportions above, and that a single scale covers a 6 inch square area, Smaug would have 2,040 scales on his body. We'll subtract 5% to account for the unprotected area that eventually led to his death, for a total of 1,938 scales that are covered with diamonds.
The article again lays out some basic figures and assumptions:
According to Diamond Helpers, diamonds above 5.99 carats are priced individually, so let's simplify and assume that all of Smaug's diamonds are 5.99 carats, priced at approximately $16,700 per carat or just over $100,000 each. Fifty diamonds per six-inch square dragon scale seems adequate to ward off most arrows
So in other words, each of Smaug's scales is worth $5,000,000 USD. With 1,938 of them like that, he has a total of
$9,690,000,000 USD worth of diamonds.
Now, that just leaves the Arkenstone.
The Hobbit tells us that it's worth 1/14 of the hoard's total value. So, let's run the numbers. The diamonds and coins together have a total value of $22,568,000,000 USD. To get the total value of the Arkenstone, we'll need to get the total value of the hoard and subtract the value of the coins and diamonds from that.
Since we don't want to skip to the magic number too early, we'll multiply 22,568,000,000 times 1.076923 (the percentage value of 14/13) and then subtract 22,568,000,000. This leaves us with $1,735,998,264 USD. We'll round that up to give the Arkenstone of Thrain a final value of
$1,736,000,000 USD.
Add them all together and you get a total hoard value of
$24,304,000,000 USD, in 2011's money.
So yeah, that hoard entering the market probably did throw off Middle Earth's economy pretty good.