Let’s take a look of one of my favorite forms of gold bullion: the one-ounce American Gold Eagle bullion coin. There are Gold Eagles in fractional weights as well, but let’s focus on the flagship coin today.
Like all bullion coins, the one-ounce Gold Eagle has no true numismatic value, because it’s not intended for hobbyists; it is, in fact, one of the more effective, compact means for active investors to acquire physical gold. Nonetheless, it’s a very striking coin, with the original Saint-Gaudens double-eagle Liberty design on the obverse, and a soaring eagle device by Miley Busiek on the reverse. It’s also stamped with a face value of $50 for trade purposes, making it legal tender — though, of course, it’s worth substantially more than that.
You might expect a one-ounce coin to weigh an ounce, but in fact the one-ounce Gold Eagle weighs 1.0909 troy ounces. That’s because the gold alloy contains 3% silver and 5.33% copper in order to harden it; pure, 24 karat gold is too soft to use for most coinage, so all Gold Eagles are 91.67% pure. The excess weight comes from the extra metal necessary to bring up the gold content to a full one troy ounce.
For those who like stats, the one ounce American Gold Eagle measures 32.7 millimeters in diameter, and is 2.87 mm thick. The edges are milled (e.g., they’re marked with tiny ridges, like a dime or quarter) to discourage removal of even tiny amounts of gold from the edges by grifters. At more than $1,350 per ounce at the moment, even those tiny amounts could quickly add up.
Incidentally: one of the reasons I like the American Gold Eagle so much is that they’re backed by the full force of the United States government, since they’re minted by the U.S. Mint. The content, weight, and purity of each coin is guaranteed by federal statute.