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Q & A: Is gold magnetic?

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Q:
Is gold magnetic?
- shawn johnson
winchester, ma, usa
A:

Shawn -

Pure gold is not magnetic. That is, it doesn’t form a magnet on its own. If you put it in a magnetic field it will magnetize a tiny bit, but only so long as it’s in the field. and the direction of the magnetizaqtion makes it weakly repel the magnet.

There are alloys of gold, for example gold with more than about 20% of the atoms replaced by iron, which do magnetize on their own, at least when they are very cold, much colder than room temperature.

-Tamara (w Mike)


(republished on 07/13/06)

Follow-Up #1: magnetic silver?

Q:
Is silver magnetic?
- Anonymous
A:
Nope, silver is very similar to gold. It does not turn magnetic on its own. In a magnetic field it magnetizes a very tiny amount, in the direction to repel the field.

Mike W.

(published on 12/19/06)

Follow-Up #2: Gold and magnets... almost no attraction

Q:
In reference to the question, "will a magnet pick up gold?", I have lost a white gold wedding band in my yard... we have tried using a metal detector only to find out that it wonít pick up gold either... or we just donít have the right one. We were wondering if using a magnet would work... but according to this it wonít... any other ideas?! Thanks!
- Lacy (age 24)
Winston-Salem, NC USA
A:

Magnets strongly attract materials (like iron) which already themselves have magnetic domains.   They do not significantly attract many metals like gold, aluminum, silver, and even some types of high-chromium stainless-steel, which lack such domains. In fact, pure gold is slightly repelled.  A metal detector, if sensitive enough, should pick up the signal from a gold ring. 

LeeH and Mike W.


(published on 06/25/07)

Follow-Up #3: Magnetic test for gold?

Q:
can i put a magnent to my jewelry to tell if it is real gold or not?
- Anonymous
A:
The magnet test will only show whether or not the ring is made of iron or other material with a high magnetic susceptibility.  For example if the ring were made of aluminum it would not be attracted, similarly as the gold ring.   If it is attracted, then it certainly is not pure gold. However, if it's not attracted, that doesn't show that it is gold.

LeeH

(published on 11/11/09)

Follow-Up #4: magnetic classification

Q:
As a 12 year-old student, are we supposed to classify gold and silver as a magnetic material or a magnetic material?
- Jessica (age 12)
Singapore
A:
I'm sure that whoever is asking you this would not want you to classify these materials as "magnetic". On their own, they do not produce magnetic fields. They scarcely respond when subjected to large magnetic fields.

Mike W.

(published on 09/05/10)

Follow-Up #5: does a magnet stick to gold?

Q:
should a magnet stick to gold,i found two pieces of gold-colored metal on sticks to a magnet and one doesnt.
- ononomis (age 11)
fl.
A:
The one that sticks to the magnet is not gold. The other one also may not be, the magnetic test doesn't tell.

Mike W.

(published on 07/25/11)

Follow-Up #6: magnets picking up gold coins?

Q:
Hi, I'm a little bit confused by your answer and a news video I saw recently. It was a video clip of a Canadian Bullion truck crash that spilled $5 million dollars of gold coins over the highway. They were using one of those powerful crane mounted magnets like would be used at a scrap yard. The gold coins were jumping up and sticking to the magnet. Since I would assume that the gold coins in the Canadian Bullion truck I would assume were Canadian Maple Leaves which are supposed to be 99.999% gold why were they attracted to the magnet? Thanks in advance for your help. All the best, Ted Sudol
- Ted Sudol (age 62)
Ringwood
A:
I looked at that news video.

You're confused? How do you think we feel?


One thing that one might think- that the weak paramagnetism of simple models of metals could be involved- doesn't work because gold is slightly diamagnetic.

There seem to be several possibilities:

1. The coins have magnetic impurities.

2. The magnets are electromagnets and use some tricky spatial pattern of ac fields to use eddy currents to pull up the conducting coins. (Simple patterns would repel the coins.)

3. There's some sort of hoax.



Mike W.

(published on 03/31/12)

Follow-Up #7: coins: loonies and toonies

Q:
just regarding the spilled coins : Those coins were gold and silver Coloured but were not Gold or Silver lol they are what we call Loonies and Toonies and are only 1$ and 2$ coins and are NOT gold or silver lol and are in fact very magnetic ;)
- Richard E (age 28)
Calgary Albert canada
A:
Thanks. This now makes sense.

Mike W.

(published on 06/03/12)

Follow-Up #8: magnets weakly repel gold

Q:
I was going to buy some gold braclets and I have a real hevey magnet.i dont care what anyine saids if a magnet bearly pulls it itd not real gold.you are saying that a magnet will bealy pull it if it is real gold.that is not true I have been buying gold for years and I have bought some that the magnet bealy picks it up I bought it and took it to thevpawn shop and it wasnt real.you need to delete this post because people are buying gold and getting ripped off.they work hard for there money and to buy something that is not real and give it to there girlfreind then it ends up turning and some people cant wear fake gold.i know I cant.
- deborah (age 50)
fla
A:

We say repeatedly in this thread that magnets do not attract gold. In fact, they repel it very weakly.

Mike W.


(published on 08/13/13)

Follow-Up #9: Canadian coins: gold?

Q:
I saw an answer you posted about some canadian truck that spilled gold coins and they used a magnet to lift the coins. Whats exactly the reaction of gold to eddy currents ? If i make a magnetic field that changes its polarity can i lift tiny parcticules of gold ?
- Antonio (age 24)
zapopan
A:

Those coins aren't really gold. See above.

An ac electromagnet will repel gold, because of the eddy currents.

Mike W.


(published on 09/16/14)

Follow-Up #10: magnetic panning for gold

Q:
thank you so much for answering my question regarding whether or not gold is magnetic. the reason I asked the question is my son read that there is gold floating in sea water and in streams (and I explained that people used to pan for gold). He wanted to know why you just donít put a magnet in sea water, or a stream, and let it collect the gold? as a dad, I really didnít have a good answer for him....do you?
- shawn johnson
winchester, ma, usa
A:

Shawn- I guess the answer is just that the gold magnetizes so little even in a strong field that you can’t pick it up. You may not have much pure gold lying around, but you probably have some copper wire, which has similar magnetic and electrical properties. Your son can try picking it up with a magnet. No answer beats a nice experiment.

Mike W.

p.s. It turns out gold and copper are very weakly diamagnetic, which means they'll be slightly repelled by the magnet, unless they have magnetic impurities in them.


(republished on 07/13/06)

Follow-Up #11: Using magnets to pick up gold

Q:
There was a question on if gold is magnetic and the answer was yes slightly. I was wondering if it is possible (and how efficiant) to "pick up" gold flakes (as small as 1 micron) with a magnet?
- Andrew (age 21)
Bellevue Community College, WA
A:
If you have a magnet that is strong enough, you can pick up even weakly paramagnetic materials. Actually, whatís important is not the strength of the magnet but how non-uniform the field is. So making the magnet with a sharp tip might help pick up small paramagnetic objects. However, it turns out gold is weakly diamagnetic, so that magnetic tip would actually repel it a tiny bit.

There is a version of this which may be more successful, though. If the magnetic field is both non-uniform and alternates in time, then the magnetic field will generate eddy currents in the electrically conductive gold flakes. These eddy currents will oppose the change in magnetic field, and the net effect will be to repel electrically conducting flakes from the alternating magnetic field. There may be other kinds of electrically conducting flakes in your sample, but gold is one of the better electrical conductors, and this level of separation may already be a big step forwards.

Tom

(republished on 07/13/06)

Follow-up on this answer.