How a Chunk of Raw Gold Becomes a Coin

Gold nugget before being refined into coins

There’s nothing like a new coin to add to your collection of bullion: the shine of the metal and the intricate designs that make each coin a beauty to behold. But, long before that gold, silver or other precious metal was stamped at the mint, it lay buried in rock.

So how exactly does gold get to that shiny coin stage?

Here’s a quick rundown:

Step 1: Mine and Extract

Gold ore is rock that contains seams of gold within it. Miners use blasts and drilling to remove gold ore from the earth in big chunks.  The gold then has to be extracted from the ore through a complicated process that involves crushing the rock into a slurry paste, dissolving the gold through chemical reactions and then making the gold solid again through other chemical reactions.

Extraction is a very energy-intensive process that only yields around six grams of gold for every ton of ore.

Step 2: Smelt

Once the gold is extracted, it has to be smelted. Smelting involves heating the gold to a very high temperature (1943°F) for several hours so that the impurities still clinging to the gold particles can be separated off. Smelted gold is then poured into molds that shape the gold into bars.

Step 3: Assay

Though the gold’s impurities have been mostly removed through the smelting process, the gold then has to be assayed, or assessed, for its purity. All gold must be refined to a purity of 99.9 percent.

Step 4: Alloy

Pure gold is very soft, making coins less durable. As a result, some coins like the American Gold Eagle incorporates different metals into the gold to create a more durable alloy. These alloys, which are still mostly gold, are what a mint will then use to make the coins that end up in your collection.

Whether gold coins are pure gold or an alloy, it takes a lot of work for a seam of gold deep underground to become a coin. Learning about the intensive process required to get the gold from the ground to your hands can make your newest bullion addition seem even more precious!

Continue learning: How Does a Coin Get Its Design?