The question of transforming one substance into another, known as elemental transmutation, has persisted for millennia, driven by the lure of creating gold. Gold is a chemical element defined by its atomic structure, having the chemical symbol Au and an atomic number of 79. This number signifies that every atom of gold contains exactly 79 protons within its nucleus, which is the unchangeable identifier of the element. Transmutation requires a change in this foundational number, moving beyond traditional chemistry and into the realm of nuclear physics. The modern scientific answer is a qualified “yes,” though the process remains practically infeasible.
The Alchemist’s Dream
For centuries, the quest to create gold from base metals like lead was the central focus of alchemy, an ancient tradition that blended philosophy, mysticism, and proto-science. Alchemists pursued the mythical Philosopher’s Stone, which they believed held the power of chrysopoeia, or gold-making. This pursuit was rooted in the Aristotelian idea that all matter was composed of four basic elements, and that base metals were simply “immature” versions of the perfect metal, gold. The goal was to accelerate this supposed natural maturation process, transforming a common metal into a noble one. Although alchemists never achieved true transmutation, their extensive experimentation laid the groundwork for modern laboratory techniques and the discovery of many chemical compounds.
Chemical Limitations of Making Gold
While alchemy was a precursor to modern chemistry, it failed because chemical reactions are fundamentally incapable of altering an element’s identity. An element is defined exclusively by the number of protons in its nucleus, and chemical processes only involve the electrons orbiting that nucleus. Chemical reactions occur when atoms share, gain, or lose electrons to form molecular bonds, which changes the substance’s chemical properties but leaves the nucleus untouched. Changing an atom of lead (82 protons) into gold (79 protons) would require the removal of three protons from the nucleus, a change that demands energies many orders of magnitude greater than any chemical process can provide. This distinction establishes a clear scientific boundary: chemistry governs compounds, but nuclear physics governs elements.
Nuclear Methods for Creating Gold
The scientific creation of gold is achieved through artificial nuclear transmutation, a process first successfully executed in the 20th century. This method involves using powerful instruments, like particle accelerators or nuclear reactors, to bombard a target element with high-energy particles to force a change in its nuclear structure. Elements closest to gold on the periodic table—mercury (80 protons) and platinum (78 protons)—are the most feasible starting materials.
One verified technique involves bombarding the stable isotope mercury-196 with high-speed neutrons, causing it to capture a neutron and become the unstable mercury-197. This unstable isotope then undergoes electron capture over a half-life of about 64 hours. During electron capture, a proton in the nucleus captures an orbital electron, turning the proton into a neutron and thus reducing the atomic number by one, successfully yielding stable gold-197 ($^{197}$Au). Other methods have successfully created gold by removing three protons from lead atoms or by bombarding bismuth with carbon and neon nuclei, demonstrating that the process is physically possible. These experiments confirmed that the alchemists’ dream could be realized, but only by employing the extreme forces of the atomic core.
Why Manufactured Gold Isn’t Used
Despite the scientific success of transmutation, manufactured gold remains impractical for commercial use due to immense energy costs and minuscule yields. The energy required to run a particle accelerator for the necessary bombardment is astronomical, making the synthesized gold trillions of times more expensive than gold extracted from the earth. For instance, one notable experiment at CERN produced an estimated 90 picograms of gold over three separate experimental runs, an amount too small to see with the naked eye.
Furthermore, the gold produced by nuclear reactions often consists of unstable, radioactive isotopes, which are unsuitable for jewelry or financial investment. For example, some synthesized gold requires nearly 18 years in storage before its radioactivity decays to a safe level for handling. With the all-in sustaining cost of mined gold historically hovering around $950 per ounce, the natural process remains vastly more profitable and scalable than any form of nuclear alchemy.