Gold has been known for more than 5500 years as an attractive and highly valued metal. While it is sometimes found in nature as the free metal, a large quantity of gold is found in conjunction with calcite, tellurium, quartz, zinc, copper, and lead.
Scientists have spent decades studying gold and discovered that its properties differ on macro and nano-scale. It’s quite complex to explain, but if you are looking for a short answer, gold is non-magnetic.
Pure gold is not attracted to magnets. However, anything less than 24-carat gold contains other materials, such as iron or nickel, which make it harder and more resistant to scratches. Such impure gold pieces become slightly magnetic under a large magnetic field.
This doesn’t mean you can reliably test your gold jewelry using a magnet. If it is not attracted to a magnet, it might contain non-magnetic materials such as aluminum, copper, or silver. So even if your gold isn’t magnetic, that doesn’t guarantee that it’s pure.
Now let’s discuss the magnetism of gold in detail.
Properties of Gold
Gold, in its pure form, is soft, dense, and malleable metal with a slightly reddish yellow appearance. A single atom of gold consists of 79 protons, 79 electrons, and 118 neutrons. Because of excessive electrons, it is highly conductive to electricity and used for electrical wiring in certain high-energy applications.
Gold is solid under standard conditions and is one of the least reactive metals. It is an excellent conductor of heat and electricity. Unlike other materials like silver and copper, gold doesn’t tarnish and remains conductive for an extended period of time.
This metal is extremely ductile. It can be drawn out into very thin wires. A single ounce of gold can be drawn into 50 miles of thin gold wire.
And since gold is also malleable, it can be flattened into very thin sheets. One ounce of gold can be made thin enough to cover over 9 square meters of area.
Why Is Gold Not Magnetic?
To understand this, we need to know what makes a material magnetic. The characteristics of magnetism in materials come from electrons and how they are distributed in their configuration.
Every metal contains a certain number of electrons based on their atomic weight and atomic number. The electrons and protons in the atom arrange themselves in the most efficient way possible.
The electron configuration of a gold atom
More specifically, electrons are arranged in shells around the atom’s nucleus. They move in atomic orbitals or subshells. Electrons moving closest to the nucleus have the lowest energy, while the ones moving further away have higher energy.
Some atoms have unpaired electrons in their outmost shell. These unpaired electrons spin freely and contribute to magnetism. Higher the number of unpaired electrons, the more magnetic the material is.
Iron, for example, usually has four unpaired electrons in its outermost shell. Therefore, it is strongly attracted to magnets. Gold, on the other hand, has only one unpaired electron, so it is less likely to form a net magnetic pole.
Furthermore, the magnetism of materials can be grouped into three primary categories.
- Diamagnetism is a form of magnetism whereby some materials are repelled by an externally applied magnetic field.
- Ferromagnetism is a fundamental mechanism by which some materials are attracted to magnets or form permanent magnets.
- Paramagnetic materials are weakly attracted by an external magnetic field. They form induced magnetic fields in the direction of the applied magnetic field.
Since gold is both diamagnetic and paramagnetic, effects can cancel each other out. There exists no “special” magnet that can overcome both effects or strengthen the effects of either only. Thus gold is neither attracted nor repelled by a magnet.
How To Tell If Gold Is Real?
An impure form of gold, such as 18-carat and 22-carat gold jewelry, consists of ferromagnetic materials. These materials are added to make gold harder and more resistant to wear or warp.
In such cases, the magnetism of gold depends on the metal fused into it. For example, if manufacturers mix gold with iron, it will yield a highly magnetic alloy. If mixed with silver, it will result in a non-magnetic white gold.
Since gold jewelry can contain a variety of materials, you cannot use magnets to accurately test gold’s purity. The only thing you can ensure is that if your gold is attracted to a magnet, it is not pure gold.
Magnets can be useful for testing gold coins and bars. If a seller claims that the gold coin is over 99% pure, then it shouldn’t be affected by a magnet.
Other useful methods for determining the purity of gold:
Look for hallmarks/trademarks: Every gold and silver jewelry purchased in the United States is marked with a quality trademark.
Conduct acid test: Gold dissolves in aqua regia (a mixture of hydrochloric acid and nitric acid) and becomes dull. So make sure that you don’t use this method unnecessarily and with valuable coins.
Use X-ray spectrometer: These testing machines measure the content of gold and other precious metals without damaging them. Niton DXL precious metal analyzer, for example, can determine the presence and concentration of more than 22 precious metal and trace alloying elements.
Recent Studies On Gold Magnetism
Gold can be magnetized by applying heat
In 2016, a team of researchers at Tohoku University, Japan, discovered that gold could be magnetized under the heat generated by a temperature gradient.
The study also highlights the electron transport property altered by spin injection and thus provides a versatile approach for the generation and detection of non-equilibrium magnetization in ordinary metals.
Magnetism observed in smallest gold cluster
On the macro scale, gold is classified as diamagnetic, which means it can be repelled by a magnetic field, but can’t form a permanent magnet.
However, things get really weird when you start observing them at the nanoscale. Small clusters of gold atoms show paramagnetic properties, which means they can attract other magnetic metals.
In 2017, researchers at the Federal University of Rio Grande, Brazil, analyzed the smallest possible gold cluster, particles of just two atoms. Their calculations revealed that in the cluster, the two unpaired electrons (one gold atom has one unpaired electron in its outmost shell) do not form a pair. Instead, they are more stable on their own.
The effect gets weaker as the cluster becomes bigger. This means the larger the gold particle, the weaker its magnetic characteristics.
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Frequently Asked Questions
Can metal detectors find gold?
Almost all metal detectors are designed to locate gold, platinum, silver, and bronze. They operate at a higher frequency rate, transmitting an electromagnetic field from the search coil into the ground. Target metals, such as gold, within the range of the electromagnetic field, become energized and retransmit an electromagnetic frequency of their own.
Modern gold detectors operate between 0-75 kHz. They utilize multiple internal coils working together simultaneously as both transmitter and receiver.
Multi-purpose metal detectors are very effective at signaling precious metals at different terrain. Fisher 22, Garrett Ace 400, Bounty Hunter Legacy 2500 are some of the popular entry-level jewelry detectors.
Is gold attracted to static electricity?
Fine powder of gold or gold leaf is attracted to statically charged objects. This happens due to the phenomenon called static electricity. When you rub two objects, one loses some of its electrons to the other. The object that loses electrons becomes positively charged, while the one that gains electrons becomes negatively charged. The opposites then are attracted to each other.
How much gold is there in the world?
Chemical analysis of rock samples shows that the top four kilometers of Earth’s crust contain about 122 billion metric tons of gold. Only a tiny portion of that is concentrated enough to mine.
Ocean waters also hold a significant amount of gold. On average, there is 1 gram of gold for every 100 million metric tons of ocean water in the Atlantic and North Pacific.
So far, humans have discovered 244,000 metric tons of gold. Most of them come from four countries: China, Australia, Russia, and United States.
Which Industry uses the most gold?
The jewelry industry accounts for more than 50% of global gold demand. China and India are by far the largest markets in terms of volume, accounting for more than half of the current global gold demand.
For centuries, gold has been largely used as an asset class. Many governments, institutions, and individuals hold gold for investment purposes. Modest allocation to gold has been proven to protect and improve the performance of an investment portfolio.
About 8% of the global gold demand is used in electronics, medical, and technological applications. In fact, most of the ways that gold is utilized today have been developed only during the last 30 or 40 years. This trend will likely continue.