Is copper ferrous or non-ferrous? Copper is a non-ferrous metal. It contains no iron, a magnet doesn’t attract it and it doesn’t rust: over time it develops a dark or greenish patina. The same goes for aluminium, brass, bronze, lead and zinc. Stainless steel, on the other hand, is ferrous, even though a magnet often won’t stick to it.
Here is the answer metal by metal, and how to check it yourself. The full definitions and the properties of each family are in our guide to ferrous and non-ferrous metals.
Which metals are ferrous and which are not?
| Metal | Ferrous? | Attracted by a magnet? | How to recognise it |
|---|---|---|---|
| Iron and carbon steel | Yes | Yes, strongly | Dark grey; corrodes with reddish rust |
| Cast iron | Yes | Yes | Grey, rough surface; grey iron snaps rather than bends |
| Austenitic stainless steel (304, 316) | Yes | No, or only very slightly | Bright grey, doesn’t rust |
| Ferritic stainless steel (400 series) | Yes | Yes | Similar to 304; common in household appliances |
| Copper | No | No | Reddish; dark or green patina over time |
| Aluminium | No | No | Light grey and very lightweight |
| Brass | No | No | Golden yellow |
| Bronze | No | No | Golden brown, darker than brass |
| Lead | No | No | Bluish grey, very heavy and soft |
| Zinc and zamak | No | No | Light grey; zamak comes as die-cast parts |
| Nickel | No | Yes | Silvery grey; rare as loose scrap |
Is copper ferrous or non-ferrous?
Non-ferrous. Copper is a chemical element in its own right (Cu), not an iron alloy, and a magnet doesn’t attract it at all. It is the best electrical conductor after silver, which is why you find it in cables, motor and transformer windings, and water and air-conditioning pipework.
What can happen, though, is that the copper comes attached to steel: an electric motor (copper windings on a core of electrical steel laminations), a mixed radiator or an armoured cable. The magnet will stick to the item, but not to the copper. As scrap, these items are sorted separately, because the two metals have to be separated before they can be recovered. How copper is recycled and what determines its value is explained in how copper is recycled, and the grades we sell are listed under copper.
Is aluminium ferrous?
No. It is a light non-ferrous metal, at about 2.7 g/cm³, just over a third as dense as steel. It isn’t magnetic and doesn’t rust, because a thin layer of its own oxide protects it. You find it in window extrusions, drinks cans, wheels and sumps.
Watch out for extrusions with steel fittings, screws or reinforcements: the magnet will stick to those parts, not to the aluminium. There is more about its grades under aluminium.
Is stainless steel ferrous?
Yes. Stainless steel is steel, in other words alloyed iron, with at least 10.5% chromium. The confusion comes from the magnet. Austenitic stainless steels, such as 304 and 316, which are the most common in the food and chemical industries and in kitchenware, are barely magnetic because of their crystal structure. Ferritic grades in the 400 series, such as 430, are magnetic.
There is a further subtlety: 304 stainless that has been bent, pressed or machined can become slightly magnetic in the deformed areas. So a stainless steel that ‘sticks a little’ isn’t necessarily worse. To know for certain which alloy it is, it has to be analysed with a spectrometer, which is how we sort stainless steel before selling it.
What about brass, bronze, lead and zinc?
Are brass and bronze ferrous?
No. Both are copper alloys: brass is copper and zinc; bronze is copper and tin. Neither is magnetic. If a magnet sticks to a tap or a part that looks like brass, it is most likely brass-plated steel, which is common in cheap screws and fittings. We explain how the two differ in brass vs bronze: differences and applications.
Are lead and zinc ferrous?
No, neither is. Lead is a very dense non-ferrous metal (about 11.3 g/cm³) and so soft you can scratch it with a fingernail; most of the lead that is recycled comes from batteries. Zinc, light grey and somewhat brittle, turns up in gutters, roofing and zamak die-castings.
One detail that catches people out: galvanised steel has a coating of zinc, but it is still steel and is recycled as ferrous scrap.
How do you do the magnet test without getting it wrong?
Use a small neodymium magnet (fridge magnets are too weak) and try it on several clean areas of the item, not just one. Then interpret the result:
- It sticks firmly: carbon steel, cast iron or ferritic stainless steel.
- It sticks slightly, or only on bent areas: probably cold-worked austenitic stainless steel.
- It doesn’t stick: a non-ferrous metal (copper, aluminium, brass, bronze, lead, zinc) or an austenitic stainless steel.
- It sticks in some places but not others: a mixed item (screws, inserts, windings) or a plated metal.
A magnet separates families, not alloys. To tell one non-ferrous metal from another you have to look at colour and weight, and to know the exact composition you need an analysis.
Why does it matter if you are selling scrap?
Because each family is processed and paid for differently. Ferrous scrap is valued on its density and cleanliness, and goes to steel mills; non-ferrous metals are valued against the market price of each metal and go to foundries and refineries. If you mix copper with iron, the copper loses value and it also contaminates the ferrous scrap, because it can’t be removed at the steel mill.
Separating before you deliver is the simplest way to get paid more. Under what we buy you’ll find the list of materials we accept.
Frequently asked questions
Are gold and silver ferrous metals?
No. They are precious metals and therefore non-ferrous. Neither is magnetic: if a ‘gold’ piece of jewellery sticks to a magnet, it has a core, a clasp or a spring made of another metal.
Why does old copper turn green?
Because of the patina. With moisture and air, the surface of the copper reacts and forms a greenish layer of carbonates and other copper salts. It isn’t rust and doesn’t mean there is iron present; in fact, it protects the metal underneath.
Can a magnet attract a copper cable?
With some cables, yes, but not because of the copper. There are cables with steel wire or tape armour, and copper-clad steel conductors, which are common in coaxial and telecoms cable. If a magnet sticks to a cable, keep it apart from ordinary copper cable, because its copper content is much lower.
If you have questions about a particular item or lot, tell us what it is and roughly how much there is. We’ll get back to you within 48 working hours.
