Gold is a fascinating gem that has for centuries played a significant role in influencing global trade and economy. The relative scarcity and difficulty in the extraction of gold have only added to the fascination, eliciting all kinds of queries about gold. One of the common questions about gold is: Is gold magnetic? This article will answer this and other related queries.
Is Gold Magnetic? Why?
This is a complex question because gold is classified as one of the densest metals in the world. It’s also not a secret that metals produce a magnetic field, which makes them get attracted to magnets. So, you would be forgiven to conclude that gold is magnetic since it’s a metal.
But scientists insist that gold isn’t magnetic. In its most basic form, gold isn’t attracted to magnetic fields. However, there are ways you can make it slightly magnetic. That is why you’ll find jewelers testing their gold pieces with magnets.
So, if your fiancé bought you a gold necklace on Valentine’s Day or your birthday and you aren’t sure if it is pure gold, the easiest way to clear the doubt is to use a magnet. If it’s attracted to the magnet, it’s not pure gold.
Most gold pieces that are attracted to magnets have been mixed with other metals like iron, silver, copper, nickel, platinum, and more. If 20 percent of your gold jewelry’s atoms have been replaced with iron, it’s likely going to stick to a magnet.
However, some of the other metals aren’t magnetic. This means that your gold jewelry may contain other metals and still pass the magnetic test. So, the best way to test its genuineness is to have it checked by a professional.
Can You Make Gold Magnetic?
As discussed above, pure gold isn’t magnetic but you can make it magnetic by mixing it with other magnetic alloys and metals like iron. Gold pieces like 18k gold or 10k gold can be magnetic, depending on the types of alloys or metals they’ve been mixed with. Even a white gold piece with a certain percentage of other magnetic metals will stick to a magnet.
You can also make gold temporarily magnetic by exposing it to a strong magnetic field. The magnetic field will be transferred to the gold piece, making it magnetic, albeit momentarily. But this is not very common because such strong magnetic fields aren’t readily available. Therefore, it’s safe to conclude that 100 percent genuine gold isn’t magnetic.
How Does a Magnet Work?
A magnet is any material whose component atoms are ordered in a way that shows properties of magnetism like attracting other iron-holding matters or producing an outward magnetic field.
Although the magnetic field isn’t visible, it generates the most extraordinary component of a magnet: a force that attracts other ferromagnetic objects like iron, nickel, cobalt, steel, and more. A magnet can attract or repel other magnets.
Magnetism occurs when the electric charges found in the atoms that form a magnet move. Atoms carry electrons, tiny particles that carry electric charges. The electrons spin around the nucleus (the core of an atom), generating an electric current that makes the electrons operate like a tiny magnet. Most materials contain electrons, but they circle in opposite directions, canceling out magnetism.
This explains why substances like gold aren’t magnetic. But in bodies like cobalt, iron, platinum, and nickel, the electrons rotate the same way, making them completely magnetic. However, this doesn’t make these magnetic substances magnets. Another strongly magnetic matter has to get into the magnetic field of a magnet to be magnetized.
A magnetic field is space around a magnet that generates magnetic force. Every magnet has north and south poles. The same poles (north + north) repel each other; while opposite poles (north + south) attract each other.
When you place a piece of iron next to a magnet, the north poles of the atoms in the iron will line up facing the same direction to create a magnetic field. This magnetic field turns the piece of iron into a magnet. An electric current can magnetize various materials, including electric wires. An electric wire produces a magnetic field when it’s carrying electricity.
Why Can a Metal Detector Find Gold?
Most amateur gold prospectors and treasure hunters use metal detectors to detect gold nuggets. However, these detectors are specially designed and calibrated for hunting gold. So, before you dash to your local store to buy a metal detector for your gold hunting escapades, you need to understand how an ordinary metal detector works and how different it is from a gold detector.
An ordinary metal detector is commonly used by security guards to detect weapons like guns and knives at public facilities. These gadgets detect metal by transmitting electromagnetic fields into the objects being scrutinized and evaluating the return signal. The electromagnetic field then generates circles of electric current, commonly referred to as eddy currents, in the conductive material (a metal object).
Metal detectors used for hunting gold work the same way, but they take this analysis further by probing inductance and conductivity. Inductance is the amount of eddy current generated by the electromagnetic field, while conductivity is the flow of the current. Once the detector determines the size of the current and its speed, it can easily compute the time constant of the target object.
Time constants vary between target objects. For example, tiny pieces of aluminum foil generate very short time constants while gold coins and other pieces of gold produce longer time constants. However, magnetic metals like iron and steel produce the longest time constants.
Treasure hunters calibrate their gold detectors to calculate time constants within the range that detects gold. However, this calibration is not always 100 percent accurate, bearing in mind the fact that several other metals fall within this range. Its accuracy also depends on the shape, size, and distance of the target object.
Fortunately, most gold-hunting metal detectors can be recalibrated on the go, allowing you to enlarge or narrow the range of your time constant.