A magnet won’t stick to brass. It slides off solid brass with no pull at all.1Osenc. Is Brass Magnetic? What Engineers Should Know About Brass And Magnets That doesn’t mean brass ignores magnets completely, since every substance responds to magnetism in some way.2Stanford Magnets. Ferromagnetic Vs. Paramagnetic Vs. Diamagnetic Brass pushes back on a magnet very slightly, a quirk far too faint for your hand to notice. That missing pull is useful: a brass-looking item that does grab a magnet is telling you something is hidden inside it.
What Brass Is Made Of
Brass is a mix of copper and zinc. Common brasses contain between 5 and 45 percent zinc, with the rest mostly copper.3Kupferverband. Copper-zinc alloys (brass) – Kupferverband Yellow brass, red brass and “cartridge” brass are all variations on that mix. Small amounts of lead, tin or other metals are sometimes added to make the metal easier to machine or to help it resist corrosion.
The zinc share changes how brass looks and behaves. More zinc generally makes it paler yellow and harder, while more copper gives a redder, more coppery tone, so color gives a rough hint about the mix. Brass with less zinc is softer and easier to shape, which is why different mixes are chosen for jewelry, plumbing fittings and ammunition cases.
Neither main ingredient is magnetic. Only a few natural metals, iron, nickel, cobalt and gadolinium, are strongly magnetic.4Magnet Academy. Diamagnetism and Paramagnetism Across the whole copper-zinc range, up to nearly half zinc, the alloy stays weakly repelled rather than attracted.5Philosophical Magazine. The magnetic susceptibility of α and β brass
Bronze is mainly copper and tin, not zinc. Like brass, ordinary bronze and pure copper also won’t hold a magnet, so a magnet can’t tell brass, bronze and copper apart.
Why Brass Doesn’t Stick: The Atom-Level Reason
Most materials fall into one of three groups: ferromagnetic, paramagnetic or diamagnetic.6NDE Ed. Diamagnetic, Paramagnetic, and Ferromagnetic Materials Ferromagnetic materials, like iron, are strongly attracted and can stay magnetized after the magnet is removed.7NDE Ed. Diamagnetic, Paramagnetic, and Ferromagnetic Materials Paramagnetic materials are only slightly attracted and lose it when the magnet goes away.8NDE Ed. Diamagnetic, Paramagnetic, and Ferromagnetic Materials Diamagnetic materials are slightly repelled and also keep nothing afterwards.9NDE Ed. Diamagnetic, Paramagnetic, and Ferromagnetic Materials
Electrons decide which group a material lands in. Each electron acts like a tiny magnet, and when electrons pair up, their spins point opposite ways and cancel.10Chemistry LibreTexts. Electronic Configurations of Cations and Anions A material with all its electrons paired has no net pull toward a magnet.11Chemistry LibreTexts. Electronic Configurations of Cations and Anions
A copper atom on its own has just one unpaired electron.12Pearson. Refer to their electron configurations to explain why copper – Tro 6th Edition Ch 9 Problem 94 That might suggest copper should be magnetic, but it’s only true of the atom alone. In a solid metal the outer electrons are shared and roam freely, so their tiny magnetic effects don’t line up in one direction.
Iron is different. Its atoms have unpaired electrons that line up with their neighbors, and the lined-up regions act together like one big magnet. Brass has no such teamwork.
What brass does instead is diamagnetic: its electrons react to a nearby magnet in a way that pushes slightly against it.13Magnet Academy. Diamagnetism and Paramagnetism Diamagnetism is present in every material, but it’s usually hidden when something stronger, like the pull in iron, is also present. In brass nothing stronger exists, so the faint push is all that’s left. It appears only while the magnet is near and vanishes the moment it’s removed, so brass never becomes a magnet itself.
That push is many thousands of times weaker than iron’s pull, and you can’t feel it even with a neodymium magnet. For practical purposes, treat brass as non-magnetic.
Why A Brass Item Might Stick To A Magnet
A firm stick on the main body of a piece suggests iron or steel in the body or base.14AJLuxe. Is Brass or Copper Jewelry Magnetic? What a Magnet Really Tells You The item is then likely brass-plated steel rather than solid brass. A pull only at a clasp or spring, with a clean body, means steel hardware, which is common and not a warning sign.15AJLuxe. Is Brass or Copper Jewelry Magnetic? What a Magnet Really Tells You
Cheap door hardware, hinges and screws are often plated steel. Costume jewelry frequently uses a plated base metal, and decorative fixtures may be steel with a brass finish. Because plating is a thin coating, the magnet still feels the steel through it. Plating tends to wear through at edges and corners first, so a scratch on a hidden spot, or a worn one, can reveal grey metal under the yellow and support what the magnet suggested.
Strength of pull matters. A strong snap usually means steel inside. A faint tug in one spot may be iron traces or a steel screw, so check for fasteners such as screws, pins or rivets before blaming the metal itself.
Iron can also sit inside the alloy. Even a trace of iron, as little as 0.07 percent, can form tiny magnetic particles inside brass when it’s heated.16Acta Metallurgica. Magnetic analysis of the precipitation of iron from beta brass Some brass may therefore show a faint pull in spots without being fake.
Some specialty copper alloys containing manganese, nickel and aluminum can be noticeably magnetic.17Journal of Alloys and Compounds. High entropy brasses and bronzes Microstructure, phase evolution and properties These are uncommon engineering alloys, not the brass in household items.
How To Test Brass With A Magnet
Use a small neodymium magnet rather than a fridge magnet, because it makes weak or local reactions easier to spot.18Oahlan. Is Brass Magnetic? A Clear Guide to Magnet Tests and Jewelry Strong magnets can pinch skin, scratch polished finishes and affect electronics.19Oahlan. Is Brass Magnetic? A Clear Guide to Magnet Tests and Jewelry Wrap the magnet in a thin soft cloth, or rest the item on a non-scratching surface.
- Hold the magnet to the main body and note whether it sticks.20AJLuxe. Is Brass or Copper Jewelry Magnetic? What a Magnet Really Tells You
- Test the clasp, ring, springs and screws separately and note which part reacts.21AJLuxe. Is Brass or Copper Jewelry Magnetic? What a Magnet Really Tells You
- Gold, silver and many fakes also don’t stick, so a non-stick result doesn’t prove brass.22AJLuxe. Is Brass or Copper Jewelry Magnetic? What a Magnet Really Tells You
Bring the magnet slowly to a flat part of the body and let it rest, because a light snap or a slight hold is easier to notice that way. Try several spots, since a steel core or insert might sit under only one area. If the item is small and light, hold it loosely and see whether it jumps toward the magnet, since a firmly gripped piece can hide a weak pull. A reaction at only one part should be tested again after that part is separated, instead of deciding about the whole item.
To confirm brass beyond the magnet, look at a scratch or worn edge: solid brass stays yellow throughout. It also feels heavy for its size, though that is only a rough clue. Tarnish turns brass brownish or greenish, not rusty orange. A jeweler or scrap yard can test composition precisely.
For scrap, a magnet quickly separates steel pieces from brass ones. Scrap buyers pay more for clean brass than steel, so pull off any steel screws before selling.
The Slow Slide Effect Isn’t Magnetism
A strong magnet sliding down a tilted brass piece moves slowly, as if dragging.23AJLuxe. Is Brass or Copper Jewelry Magnetic? What a Magnet Really Tells You A moving magnet sets up swirling electric currents in metals that conduct electricity. The drag doesn’t mean the piece is magnetic, and gold and silver do it too.24AJLuxe. Is Brass or Copper Jewelry Magnetic? What a Magnet Really Tells You
To try it, tilt the piece at a modest angle, place a strong neodymium magnet on it and watch whether it glides down slowly rather than snapping to the surface. Compare with wood or plastic at the same tilt, where the magnet slides or tumbles much faster.
The currents form only while the magnet is moving relative to the metal, so a magnet held still on brass feels no drag. Faster motion creates stronger currents and therefore stronger drag, which is why the effect is clearest with a quick pass. Drop a neodymium magnet down a copper or brass tube and it falls noticeably slower than through a plastic tube: nothing sticks, yet the metal fights the motion.
The same effect sorts scrap. Recycling plants use machines based on these currents to pull brass, copper and aluminum out of mixed waste.25Dings Magnetic Group. Magnetic Separation Recycling | Material Recovery & Recycling Magnets
Where Being Non-Magnetic Makes Brass Useful
Brass and copper are safe for compass mounts and nearby fittings because they don’t pull a compass needle off course.26American Nautical Services. Understanding Magnetic Compasses Brass fittings near a boat compass are fine, but nearby steel tools or a phone can push the needle. Keep those away from a hiking compass while taking a bearing. When replacing screws or brackets near a compass, brass or copper ones are a sensible choice. Brass screws are useful near magnetic sensors, where a steel screw could distort what the sensor reads.
Brass tools are non-magnetic and resist corrosion.27The Bombay Tools Supplying Agency. What Materials Are Used in Non-Sparking Tools? A Complete Guide They also spark less than steel, suiting lower-risk areas with flammable gas.28The Bombay Tools Supplying Agency. What Materials Are Used in Non-Sparking Tools? A Complete Guide A national standards lab chose a brass plate for leveling metal powder because powder wouldn’t cling to it and it wouldn’t spark.29National Institute of Standards and Technology. Lessons Learned in Establishing the NIST Metal Additive Manufacturing Laboratory In a workshop, brass won’t pick up steel filings and shavings the way a steel tool would.
Brass’s spark resistance is moderate, not total, and the most hazardous gas zones call for other specialty alloys. Brass is also softer than steel, so tools wear faster.