Ha!
Okay, I know that by this point I've taken this
waaay too far, and that nobody likely cares anymore, but I managed to recalculate Smaug's hoard based on the value of the coinage in D&D (as opposed to the value of the assumed coinage in the previous calculation).
The key was that the density of gold (and silver) are already known (gold being 19,300 kilograms per cubic meter, and silver being 10,490 kilograms per cubic meter), so since we know the mass of the coins (140 grains if we're assuming that fifty coins equals an avoirdupois pound; or 115.2 grains if we're assuming that fifty coins equals a troy pound), we can then calculate the volume of a given coin of each metal. Since we already know the total volume of Smaug's hoard (741.5 cubic feet for gold, and another 741.5 cubic feet for silver, as detailed above), we can plug the numbers in and figure out the results!
Remember, we're assigning silver a grain value of one-tenth gold's grain value (rounded to the nearest cent), so that it matches with D&D's listed value for gold and silver coinage.
First, the avoirdupois measurements:
The volume of one D&D 3.5 gold coin at 140 grains is 0.000016599750447490626 cubic feet. This gives us 44,669,346 gold coins in Smaug's hoard; we'll round this up to 44.7 million. Gold is $3.07 USD per grain, so one gold coin is $429.80. Multiply this by 44.7 million to get $19,212,060,000 USD in gold coins.
The volume of one D&D 3.5 silver coin at 140 grains is 0.000030541008926269694 cubic feet. This gives us 24,278,831 silver coins in Smaug's hoard; we'll round this up to 24.3 million. The adjusted value of one grain of silver in D&D 3.5 is $0.31 per grain, so one silver coin is $43.40 USD. Multiply this by 24.3 million to get $1,054,620,000 USD in silver coins.
$19,212,060,000 USD in gold coins plus $1,054,620,000 USD in silver coins equals $20,266,680,000 USD in coins in Smaug's hoard; round this up to
$20,267,000,000 USD. Add in the
$9,690,000,000 USD in diamonds embedded in his body, and get $29,957,000,000 USD. Multiply by 1.076923 and then subtract $29,957,000,000 to get $2,304,382,311 USD for the Arkenstone, round down to
$2,304,000,000 USD. Add that to $29,957,000,000 USD to get a total avoirdupois D&D 3.5 hoard value of
$32,261,000,000 USD.
Interestingly, the troy measurements come out almost exactly identical (which makes sense, since the total volume of the hoard doesn't change):
The volume of one D&D 3.5 gold coin at 115.2 grains is 0.000013659223225363716 cubic feet. This gives us 54,285,664 gold coins in Smaug's hoard; we'll round this up to 54.3 million. Gold is $3.07 USD per grain, so one gold coin is $353.66 USD, rounded up to $354 USD. Multiply this by 54.3 million to get $19,222,200,000 USD in gold coins; round down to
$19,222,000,000 USD in gold coins.
The volume of one D&D 3.5 silver coin at 115.2 grains is 0.000025130887345044778 cubic feet. This gives us 29,505,524 silver coins in Smaug's hoard; we'll round this down to 29.5 million. The adjusted value of one grain of silver in D&D 3.5 is $0.31 per grain, so one silver coin is $35.71 USD, rounded up to $36 USD. Multiply this by 29.5 million to get
$1,062,000,000 USD in silver coins.
$19,222,000,000 USD in gold coins plus $1,062,000,000 USD in silver coins equals
$20,284,000,000 USD in coins in Smaug's hoard. Add in
$9,690,000,000 USD in diamonds, and get $29,974,000,000 USD. Multiply by 1.076923 and then subtract $29,974,000,000 to get $2,305,690,002 USD for the Arkenstone, rounded up to
$2,305,000,000 USD. Add to $29,974,000,000 to get a total troy D&D 3.5 hoard value of
$32,279,000,000 USD.
So if we make a direct comparison between Smaug's hoard and a D&D 3.5 great red wyrm's hoard, Smaug wins by an even bigger margin than we thought.
In troy, Smaug has
$32,279,000,000 USD to the great red wyrm's
$595,000,000 USD (rounding up to the nearest million; see post #6).
In avoirdupois, Smaug has
$32,261,000,000 USD to the great red wyrm's
$722,000,000 (rounding down to the nearest million, see post #6).
So what can we determine from all of this? That clearly, Smaug was involved in some sort of insider-trading scandal that would have rocked Middle Earth to the core had it ever come out.
