magnetized gem

I heard that a gem hematite can be magnetized using a "complex heating
procedure", and as such used for clasping, for example. But, from another
source I heard that hematite cannot be magnetized, but that his simulated
version, called hematine, can indeed be magnetized. Which of these
statements is true? Another question - in which color versions can these
stones be found/produced, since I only know of black? Thank you!

Marijan

"m4816k" schreef ...
I heard that a gem hematite can be magnetized using a "complex heating
procedure", and as such used for clasping, for example. But, from another
source I heard that hematite cannot be magnetized, but that his simulated
version, called hematine, can indeed be magnetized. Which of these
statements is true? Another question - in which color versions can these
stones be found/produced, since I only know of black? Thank you

It is not clear to me what you mean by "magnetized".
Is that "being attracted by a magnet" or "acting as a magnet"?

Hematite is normally not attracted by a magnet.
Hematine can be picked up by a magnet.

A few years ago I tried an experiment (triggered by a book?, a website?, I
really don't remember).
That was to heat a hematite to dull red heat in a flame, after cooling the
cabochon could be
picked-up by a magnet.
And indeed, it was picked-up, but not by a complex heating procedure.

Sorry, I did not do a follow-up, to see if the hematite would loose its
"magnetism" and would
revert to the state of "not being attracted by a magnet" after a lapse of time.

Groeten,

Jaap

"m4816k"

I heard that a gem hematite can be magnetized using a "complex heating
procedure", and as such used for clasping...

Are you possibly confusing this with magnetite... a natrually occurring
weakley magnetic ore?

I can not imagine how one could magnetize hemetite. Most magnets are
destroyed by heating as a point of interest.

js


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"Jaap Bos"

That was to heat a hematite to dull red heat in a flame, after cooling the
cabochon could be
picked-up by a magnet.
And indeed, it was picked-up, but not by a complex heating procedure.

That's pretty interesting. I would sure like to know the physics of that
reaction.

js


--
PHOTO OF THE WEEK: http://schmidling.netfirms.com/weekly.htm
Astronomy, Beer, Cheese, Gems, Sausage, http://schmidling.netfirms.com

"Jack Schmidling" schreef ..

"Jaap Bos"

That was to heat a hematite to dull red heat in a flame, after cooling the
cabochon could be
picked-up by a magnet.
And indeed, it was picked-up, but not by a complex heating procedure.

That's pretty interesting. I would sure like to know the physics of that
reaction.


Yes, I would like to know that too! I'll look in my books/favorite website's to
see if I can find
that "heating tric" again.
But, as I recall after a few years, no explanation was given. Maybe it is some
sort of
re-crystallisation???

In another post in this thread you (of course correctly) pointed out that
heating above a certain
temperature would destroy a magnet.
But that is because it loses its ferro-magnetism. But the material will still be
para-magnetic, so
although it can no longer "pick up" a piece of e.g. Iron, it still will be
attracted by another
magnet.

Groeten,

Jaap

"Jack Schmidling" schreef ...

"Jaap Bos"

That was to heat a hematite to dull red heat in a flame, after cooling the
cabochon could be
picked-up by a magnet.
And indeed, it was picked-up, but not by a complex heating procedure.

That's pretty interesting. I would sure like to know the physics of that
reaction.

js

I found a reference of this in : E.S. Dana, A textbook of mineralogy, 4th ed.
1932. p. 484.

Describing the behaviour of hematite under the blowpipe it states

"is infusible; on charcoal in a reducing flame becomes magnetic"

No further explanation given!
That small piece of text "inspired" me to do that experiment, but with a normal
burner, not on
charcoal.

Groeten,


Jaap

Both Hematite (Fe2O3) and Magnetite (Fe3O4) are natural minerals
exhibiting intrinsic magnetic properties. However, Hematite is
Antiferromagnetic which means its net magnetic moment is practically
zero and Magnetite is Ferrimagnetic, namely has a net magnetic moment
when magnetized properly. To magnetize magnetic specimen, one has to
apply a very strong magnetic field to align the microscopic magnetic
domains and then remove it to be left with a permanent moment. Another
way to magnetize magnetic specimen is to heat it close to its "Currie
temperature" (the temperature above which magnetic order is lost) and
then cool it back in low field. The reverse process always applies:
heating a magnetized material to above its Currie temperature and
cooling it back in no magnetic field will result in a lost of magnetic
behavior.

Bottom line: There is no point in trying to magnetize Hematite since
its intrinsic magnetically ordered state exhibits very weak
magnetization. Magnetite is a better choice for magnetizing purposes.

Sarit.

Sarit Wolfus - Silver, Gold and Gemstones, handcrafted jewelry
http://sarit-jewelry.com

"Sarit Wolfus" schreef ...
Both Hematite (Fe2O3) and Magnetite (Fe3O4) are natural minerals
exhibiting intrinsic magnetic properties. However, Hematite is
Antiferromagnetic which means its net magnetic moment is practically
zero and Magnetite is Ferrimagnetic, namely has a net magnetic moment
when magnetized properly. To magnetize magnetic specimen, one has to
apply a very strong magnetic field to align the microscopic magnetic
domains and then remove it to be left with a permanent moment. Another
way to magnetize magnetic specimen is to heat it close to its "Currie
temperature" (the temperature above which magnetic order is lost) and
then cool it back in low field. The reverse process always applies:
heating a magnetized material to above its Currie temperature and
cooling it back in no magnetic field will result in a lost of magnetic
behavior.

Bottom line: There is no point in trying to magnetize Hematite since
its intrinsic magnetically ordered state exhibits very weak
magnetization. Magnetite is a better choice for magnetizing purposes.

Sarit.

Maybe the words "magnet and magnetized" were used a bit 'loose' in this thread
(also by me!).
What I mean is:

A steel paperclip is not a magnet.
But a paperclip can be picked-up by a magnet.
Hematite normally can't be picked up by a magnet.
Heat Hematite, after cooling it can be picked up by a magnet (Idid this
experiment)
Still, this heated hematite is not a magnet in the 'domestic' sense of the word,
since it can't
even pick-up a very small paperclip.

Groeten,

Jaap

On Sat, 10 Jul 2004 18:21:14 GMT, "m4816k"
wrote:

I heard that a gem hematite can be magnetized using a "complex heating
procedure", and as such used for clasping, for example. But, from another
source I heard that hematite cannot be magnetized, but that his simulated
version, called hematine, can indeed be magnetized. Which of these
statements is true? Another question - in which color versions can these
stones be found/produced, since I only know of black? Thank you!

Hematine, a name trademarked by Fire Mountain Gems for their
manufactured hematite, is just ground bits of hematite in resin. They
can both be magnetized either by exposure to heat or to a strong
magnetic field. They can be de-magnetized the same way. It's the
iron that makes it possible.

I don't recommend using magnetized hematite or hematine as clasps.
They'll eventually hit a magnetic field and fail.

--
Marilee J. Layman

Does Magnetite look the same as Hematite?
I have round Hematite beads that are not attacked to magnets. The square
beads look the same as the round but stick to my jewelry chest magnet. I
don't wear the square ones because they seem to cut through the coated wire
thread pretty quick.

--
Connie Ryman
Cryman Studio

"Sarit Wolfus" wrote in message
...
Both Hematite (Fe2O3) and Magnetite (Fe3O4) are natural minerals
exhibiting intrinsic magnetic properties. However, Hematite is
Antiferromagnetic which means its net magnetic moment is practically
zero and Magnetite is Ferrimagnetic, namely has a net magnetic moment
when magnetized properly. To magnetize magnetic specimen, one has to
apply a very strong magnetic field to align the microscopic magnetic
domains and then remove it to be left with a permanent moment. Another
way to magnetize magnetic specimen is to heat it close to its "Currie
temperature" (the temperature above which magnetic order is lost) and
then cool it back in low field. The reverse process always applies:
heating a magnetized material to above its Currie temperature and
cooling it back in no magnetic field will result in a lost of magnetic
behavior.

Bottom line: There is no point in trying to magnetize Hematite since
its intrinsic magnetically ordered state exhibits very weak
magnetization. Magnetite is a better choice for magnetizing purposes.

Sarit.

Sarit Wolfus - Silver, Gold and Gemstones, handcrafted jewelry
http://sarit-jewelry.com