The gold bar is one of the most recognizable symbols of wealth on earth. Its trademark sheen and appearance has served as iconography for riches throughout human history.

Gold bars are also, by definition, quite rare. All the gold ever mined by humans – roughly 200,000 – 220,000 metric tons – would fit comfortably inside a few Olympic swimming pools, and there are modern cargo ships that, in theory, could carry the entire amount in a single shipload.

As iconic as the gold bar is, however, most people never stop to think about the different steps, the different companies, or even the different countries that must work together to bring new gold bars to market. So, this page is your guide to a gold bar’s journey from the ground to your vault.

Where Gold Comes From: Mining

Gold is the stuff of stars – literally. It originated from the collision of neutron stars, then made its way into the primordial soup that came to be our planet billions of years ago.

Now, most of it sank deep into the Earth’s core. However, over time, geological processes have brought some gold into the Earth’s crust – where we could find it.

These processes have not distributed gold uniformly across the world. There are particular countries and areas that are richer in gold than others.

Those of us in the US are well aware of the California Gold Rush, and – to an extent – the other gold rushes in North Carolina and Georgia that formed much of America’s early currency and wealth. Nowadays, the US is still a top gold producer, but it is not the biggest producer of gold worldwide.

By far, the top country for gold mining is China. On average, Chinese miners recover around 380 metric tons of gold each year, and some years have borne witness to recoveries in excess of 450 metric tons. Other countries high on the list include Russia, Australia, and Canada.

Gold mining at scale is usually accomplished through one of the following methods:

• Open-pit mining – The initial surface layer of dirt and rock – known as overburden – is cleared away to reveal the gold-bearing material below. The ore recovered from these kinds of operations tends to be relatively low in its concentration of gold within the ore.
• Underground mining – Deep shafts and tunnels are dug into the ground in order to access ores with higher concentrations. Obviously, there are greater safety and logistical issues that come with this method of extraction, but the higher returns are often deemed worthy of the risk.

Now, it’s important to realize what we mean when we’re talking about mining at scale. They involve major construction equipment and move tons of ore at once. Even in the most careful of operations, there is a significant environmental impact on the area with mines.

The scale is necessary, however, due to the fact that it often takes several tons of ore to produce a single troy ounce of pure gold. For some open-pit mines, a single ounce of gold may require the processing of 60 tons of ore or more.

Extracting the Gold: Processing the Ore

Once the raw ore is pulled out of the ground, it must go through several rounds of processing before it becomes a gold bar. The initial bit of refining typically takes place at or near the mine site itself.

The first step in the process is usually to crush and/or grind the raw ore into a fine powder, as doing so makes the next steps easier. Then, water is added to the powder to create an ore goop known as “pulp.”

For large or industrial operations, the more common method to get the gold from the raw ore is to leach it out. With this method, the mill introduces a weak cyanide solution to the mixture in order to dissolve the gold away from the other materials in the solution.

Then, the workers pull the gold out of the solution using one or more different media as filters. The most common way to get the gold is to pass the solution through activated carbon, which attracts the cyanide-gold ions.

The gold is then stripped off the carbon with a hot chemical solution to break the bonds between the cyanide and gold. The gold is collected using electrowinning, in which electrified steel wool collects the gold ions.

The resulting gold concentrate is melted into doré bars, which are raw bars that are typically between 60% and 90% gold. The remaining portions of the bars are usually other metals, including silver, which made it through this initial process.

Refining: Turning Doré into Pure Gold

Now, if you’ll recall, doré bars are primarily composed of gold already. However, for the purposes of investment grade gold, their 60% – 90% compositions fall short of international standards set by organizations like the London Bullion Market Association (LBMA), whose Good Delivery specifications are generally considered to be the orthodox position for gold purity.

So, doré must undergo another round of refining at specialized refineries to become pure gold bars. These refineries can be anywhere, but tend to be in Switzerland, the UAE, the USA, or South Africa.

As before, the gold-bearing objects are melted down once again in furnaces. However, they then go through one of a few processes to remove the silver and other “impure” metals from the doré.

The two main techniques to refine into high purity gold are the following:

• The Miller Process – With this technique, chlorine gas is passed through the impure molten material. It bonds with silver, copper, and many other metals (though not all) to form chlorides. The chlorides then rise to the surface of the melted doré bar material, where they can be skimmed off. The remaining material is 99.5% pure gold.
• The Wohlwill Process – In some cases, the Miller Process produces sufficient purity. However, when even greater fineness is desired, the molten gold goes through the Wohlwill Process. In this procedure, the gold is placed in an electrolyte of gold chloride and subjected to electric current. The pure gold leaves the original sample (the anode) and is attracted to a receptor – the cathode. This process, though time-consuming, results in a gold sample that is 99.99% pure, or “four nines fine.”

Once the gold has finished being refined, it is ready to be made into investment grade gold bars.

Casting the Bar

Gold bars are made in one of two different styles. The chosen style can depend on the customer’s wishes, the published standards, or, simply, the refinery’s available machinery.

No matter the desired style, the pure molten gold is poured into a bar-shaped receptacle known as a mold. These forms are sometimes called “ingot molds.”

This process is known as casting. For some refineries, it is the last step in the process. The gold will cool in the molds and then be knocked free as a finished bar. Cast bars have a slightly rough and rounded appearance – some even refer to them as having a “rustic” look.

The other type of bar is a minted ingot. In this case, though the molten gold is poured into molds, it is also pressed with hydraulics into flat, uniform strips. These strips pass through the rollers several times until they meet precise dimensions.

Then, they are precision cut with tremendous hydraulic pressure and stamped to produce a polished bar with sharp corners. Minted ingots go through many of the same processes that mints use to make coins.

Finally, minted ingots must undergo stringent quality control measurements. In general, bars made using this second process are considered to be of the highest quality.

Stamping, Assaying & Certification

Once the bar has cooled and finished, the refinery must stamp its name and logo directly into the metal. Because most top refineries are well-known, the presence of a stamp from one of them serves as a proxy for the bar’s quality and legitimacy.

The refinery also stamps the bar with its weight and purity. Generally, the weight is listed in terms of troy ounces, while the purity statement is usually a series of nines – with or without a decimal.

Finally, the bar is likely to be stamped with a unique serial number. Thus, each bar is deemed to be its own commodity, slightly different from the others.

Some gold bars may bear stamps from assayers. Assayers conduct independent tests on each bar to certify its purity and weight, and their marks are critical for a bar’s certification under the highest global standards set forth by international bodies – primarily, the LBMA and its Good Delivery specifications.

However, refiners are willing to go to these lengths because the certification of the LBMA places a tremendous amount of credibility and legitimacy on the bar. In turn, the gold bars maintain excellent liquidity for both buyers and sellers.

From Refinery to the World

From the refinery, the finished gold bars are transported across the globe. Needless to say, these transports are some of the most tightly-guarded shipments in the world.

One key element of these transports is a clear chain of custody for them. The risk of counterfeiting and robbery is necessarily high, so it is crucial that the transfer of gold bars is a series of documented handoffs, rather than a willy-nilly dispersal across the land.

Some of the recipients of new gold bars include central banks like the Federal Reserve or the Bank of England. Others go to commodity exchanges like LBMA and the COMEX, the latter of which through COMEX-approved vaults.

Finally, many of them end up in the hands of numerous private dealers around the world, both online and in-person. Those kinds of arrangements are what allow you to purchase the same high-quality gold bars that governments trade with each other.

Of course, public buyers and exchanges tend to maintain their own secure containment facilities. Private investors typically place their gold bars within the care of private vaults and third-party storage operations.

Conclusion

For many people, a gold bar is the ultimate symbol of wealth. However, that impression actually sells this remarkable object quite short.

The small, yet heavy, bar in a vault or in a pocket is there due to an incredible journey. It is literally a piece of starlight that embedded itself deep inside our planet.

From there, it had to travel via manifest geological forces and end up in a fortuitous location, where it could be discovered by the hand of man. It voyaged across continents, experienced incredible heat repeatedly, and required precise chemistry to result in its position as a universal object of value.

Perhaps part of gold’s enduring value stems from its improbable and arduous journey from supernova to storage facility. However, let’s be honest – that signature heaviness and trademark sheen never disappoints when it’s sitting in your hand.