Gold is a chemical element defined by its atomic number 79 and its symbol Au. This dense, lustrous metal has been prized for millennia. Its existence is almost entirely the result of natural cosmic and geological processes, and the vast majority of the world’s gold supply is naturally occurring. Understanding the nature of gold requires looking far beyond Earth, to its explosive origins in the universe.
Gold’s Cosmic and Geological Origin
The formation of gold atoms requires energy levels and pressures that are impossible to generate on Earth. Scientists theorize that gold is forged in cataclysmic stellar events, specifically the intense conditions found during a supernova explosion or the collision of two neutron stars. These events feature a rapid neutron-capture process, known as the r-process, which is necessary to create elements heavier than iron, including gold. The newly formed gold atoms were then scattered across the cosmos as part of the resulting cosmic dust cloud.
This gold-enriched dust was eventually incorporated into the material that formed our solar system, including the early Earth about 4.6 billion years ago. Most of the planet’s initial gold supply sank toward the core due to its extreme density during the Earth’s differentiation. The gold we access today in the crust is thought to have arrived later, primarily delivered by meteorites that bombarded the planet after the core formed. Even then, the gold was dispersed in extremely low concentrations, often measured in parts per billion.
Geological activity was necessary to concentrate these scattered atoms into mineable deposits. One mechanism is hydrothermal activity, where superheated, mineral-rich water circulates through cracks in the Earth’s crust. As this water cools, the dissolved gold precipitates out of the solution, forming quartz veins that contain concentrated gold deposits. Another process is the weathering of gold-bearing rocks, which releases particles that are then carried by water and deposited in streambeds, creating what are known as placer deposits.
The Reality of Synthetic Gold
The theoretical creation of gold from other elements is possible through nuclear transmutation. Gold has 79 protons; elements like mercury (80 protons) or platinum (78 protons) can theoretically be converted by adding or removing a single proton from the atom’s nucleus. Early experiments confirmed this concept using particle accelerators or nuclear reactors to bombard the target element with high-energy neutrons or particles.
However, synthetic gold production is extremely impractical and costly. The energy required to strip or add a proton is immense, far outweighing the value of the resulting metal. Experiments using high-energy physics facilities like those at CERN have produced only picograms of gold, an amount so minuscule it is invisible. The cost of generating even a single gram of gold this way is estimated to be many times the current market price.
Furthermore, the isotopes of gold created during transmutation are often unstable and radioactive. This means the newly created gold would need a significant decay period before it could be safely handled or used commercially. Therefore, while nuclear physics confirms gold can be made, no commercially viable or practical synthetic gold exists for jewelry, investment, or industrial use.
Transforming Raw Gold into Usable Material
The gold extracted from the Earth is not the pure, gleaming metal seen in bullion bars and electronics. It is initially found as gold ore or, after preliminary processing, as doré bars, which typically have a purity of around 80%. This raw material contains various impurities, most commonly silver, copper, and trace amounts of other platinum-group metals. The final usable material is the result of intensive refining processes.
Refineries use industrial techniques to separate the gold from these other elements and achieve high purity levels. A common chemical method is the Miller Process, which involves bubbling chlorine gas through the molten gold to react with and remove the impurities, resulting in a purity of approximately 99.5%. For the highest standard of purity, such as 24-karat gold, the more precise Wohlwill Process is used. This is an electrolytic method where an electric current dissolves the impure gold and re-deposits it as gold of 99.99% purity onto a cathode.
This high level of purification is necessary for gold to be used in investment-grade bullion and sensitive electronics. The process transforms the naturally occurring, but contaminated, elemental gold into a marketable commodity. Therefore, while the element itself is natural, the gold product consumers and industry interact with is a meticulously processed and refined material.