"Magnetic Hematite" for sale in museums

Has anyone else seen these shiny metallic lumps that stick to each other to form chains? I have seen them in the gift shops of major museums (with mineral exhibits). This stuff is obviously synthetic. Natural hematite is not ferromagnetic. However there is no indication of this fact anywhere. Should not museums tell the truth, the whole truth, about what they are selling?

Haha...yeah, another case of people who don't know minerals selling Chinese material as it is labeled. Of course, when these "Zipper Magnets" are sent to the gift shops they are labeled as Hematite. Well, to the chinese manufacturing industry, Hematite/Iron/Magnets, it all might as well all be the same thing. English is not the first language. Museums should certainly make every attempt to provide accurate information on the minerals sold there, but you know...it is a freakin gift shop. I think the curators have a bit more to do than to make sure the garnets are labeled with the right name and that zipper magnets are not sold as Hematite. I guess you could send out a press release. Get to work Howard! =) Those faxes don't send themselves!

It's unfortunate that it seems that almost EVERY museum giftshop sells fraudulently-created "mineral" items that are so common they are ubiquitous in gift shops worldwide. In particular the four most common are:

* "Citrine" (baked Amethyst)
* "Agate" (artificially dyed)
* "Smoky Quartz" (irradiated clear quartz from Arkansas or China)
* "Bornite" (chemically treated Chalcopyrite lumps)

Museums that should know better, such as the Natural History Museum in London, and the Royal Ontario Museum in Toronto are amongst the culprits. Can't someone from the departments there have a strong word with the buyers in the gift shop to say that either the stuff needs to be labeled to explain that it's not natural, or it needs to be withdrawn.

There are enough true natural materials available that these particular fake items don't really need to be stocked.

Jolyon



Edited 1 time(s). Last edit at 04/18/2008 09:35AM by Jolyon Ralph.

Hi Jolyon, I have just returned from the European continent where I visited several gem and mineral shows, at each one they were selling these magnets as "Magnetic Hematite"! When I pointed out to the dealers that these were not hematite, and that hematite is not magnetic the told me it was from a new find. I told them their mistake was labelling them as hematite, but they took no notice. This sort of trading makes me very angry indeed. Spencer.

When I worked in the London Geological Museum (1970s/early 80s), one of my tasks for a while was to "view & vet" the incoming mineral specimen stock for the Museum shop (at the request of the shop manager). The main reason my input was requested was to check for correct labelling. I couldn't always say whether the localities of specimens such as crystals of pyrite or lumps of massive talc were correct of course, but at least I could prevent the worst of the rubbish & errors getting through. Most were correctly identified, quite genuine & untreated, if rather ordinary pieces of common minerals, and they were primarily for customers such as school parties or intended as "pretty souvenirs" for casual visitors, rather than serious collectors. Synthetic "chalcanthites" and alum crystals were regular rejects, and there were aso occasional examples such as spinels labelled as zircon and a quartz prism (with the termination knocked off) labelled "beryl". I was also able to advise that pieces such as powdery massive cinnabar or realgar were kept behind the counter, and not put out on the low shelves in the outer part of the shop, where the primary school vistors could handle them when they browsed - which was quite commonly during their lunch break, just before they settled down to eat their sandwiches!

To me it was important that young collectors just starting out were not misinformed about what they were spending their pocket money on, even if it was only a piece of massive pyrite or a rather chipped quartz crystal, and it only took a short while to scan over the trays of each delivery to spot and reject the obvious rubbish or wrongly labelled pieces. I would have thought that any major museum would consider this a valuable part of their educational function, and use of even a junior mineralogist's time, but perhaps if this is no longer happening, it is yet another symptom of cuts in science funding, and the "dumbing down" so prevalent in the world of media & education. At the time of the major changes in the Museum management in the 1980s, I remember remarking that it seemed to me that what I saw as the primary functions of a Museum - conservation, education and research, had been replaced by glossy trivial entertainment aimed at mass appeal; what I termed the "Disney" syndrome.

However, ramble over and back to the OP: "Magnetic Hematite"

In the context of doubtful pieces from Museum shops etc, a piece I was once asked to check by a friend who knew of my Museum work, was one of several crystals she had been given by another friend as "magnetic haematite". As she was rather doubtful about them she had brought them to me for another opinion. The one I tested is a single flat crystal about 30mm long, apparently a rather pitted, distorted scalenohedron, with an almost adamantine lustre (similar to a good Elba haematite) and quite obviously weakly ferromagnetic. It will swing a compass needle, and althought an ordinary hand magnet will not actually lift it, it gets noticeably lighter in the hand when the magnet is brought close above it. It is attracted to the magnet when suspended by a piece of cotton, and it can be tipped from a position of unstable balance when the magnet is brought near it.

The first impression was that it must be a pseudomorph of magnetite after haematite, but as SG and hardness are not reliably distinct for magnetite and haematite, I ran a Debye-Scherrer XRD analysis on a small sample scraped from several edges with a diamond file. All the sources gave red powder, and the XRD pattern was definitely that of haematite, with no indication of magnetite or maghemite lines on the film.

Following my tests, she gave the crystal I tested to me. Without grinding up the whole crystal for analysis, there is no way to be certain that it does not contain any inclusions of magnetite which are responsible for the magnetism, but I cannot envisage an environment which would allow a single crystal of haematite to include a significant mass of unoxidised magnetite in its core, and as all its features except for its anomalous magnetism (crystal form, lustre, streak, and XRD pattren) are all consistent with haematite, it is now in my collection labelled as "Magnetic haematite". (The locality given by the collector was Arzannah Island, Abu Dhabi, where these crystals are apprently called "black diamonds" by the locals!)

Pete N.

Pete,

I still have a large number of those 1 pound specimens in plastic boxes that I bought from the shop as a kid at that time. Where now could you buy a Legrandite in a box from a museum gift shop? Great times, and thank you for your efforts.

It probably, in no small way, contributed to me doing what I do now.

Jolyon

Wasn't this synthetic BaFe12O19 or some isotypic plumboferrite-type hard magnet?

Hello all
It is a fact of life in museums these days. At one point we (ROM) had a mineral shop that was vetted by the department, but those days are long gone. Most museum shops arent run by the museum they are housed in, but by a 3rd party company. We have no control what they buy, nor how they display and label the objects/specimens. We have tried to set our buyer up with reputable mineral dealers, but they still end up buying the low cost, big mark up junk that is mislabeled.
please see this link to find out more information ..
[www.noteaccess.com]
very best
Katherine
Collections technician
ROM

Jolyon, you have a half kilo (i.e., a pound) of legrandite? Or do you mean the specimen cost one pound?

My keyboard at work doesn't have a £ symbol!

Jolyon

I am gratified that so many people have responded to my initial posting. Museums are often the first place members of the "public" especially children are exposed to the world of minerals. I have sent the url of this discussion to Dr. Anthony R. Kampf, the webmaster for the Society of Mineral Museum Professionals, who in turn has sent it to the membership of the society. He has also checked the shop of the museum where he is curator and found no "magnetic hematite".

A "magnetic hematite" bead I got at the Munich show turned out to be strontium ferrite - definitely completely artificial, no natural hematite used in its production at all.

doesn't hematite become magnetic upon heating by changing oxidation state to magnetite but of course the properties would somewhat alter maybe through controled heating you could selectively convert minute amounts in a crystalyou mightnot notice. but in the case of these "zipper magnets" this is not likely

Investigation shows the "magnetic hematite" available here to be a barium-strontium ferrite magnet: (Ba,Sr)Fe12O19 that has the magnetoplumbite structure. The average grain size of the ceramic is 5-10 microns, and the porosity is 10-15%. In addition, the magnetic field strength of this material is much larger than that of any magnetite specimen.

It is sold here with a rather misleading label/disclaimer:
"Magnetic hematite is formed from finely powdered iron oxide and heated until it granulates. During this process a strong magnetic field is applied to the material so that the molecular poles line up to form a permanent magnet. Then it is cut into smaller blocks and polished to create magnetic hematite."

Although useful for demonstrating and teaching magnetism, it is very unfortunate that it is being marketed using mineralogical terminology. It is simply a synthetic ferrite magnet,

I've added a magnetic hematite page into the main database.

Thanks everyone, espeically to Andrew.

Jolyon

I did something I very rarely do and that is to buy some new age junk.

I purchased a strong of Hematite beads simply because I liked the look of it.
I noticed the beads were magnetic, so had some serious doubts. After it broke, I ran one across a streak plate - the streak is an unattractive dark brown, not a trace of red. Ditto under the microscope. Left in damp, they rust a darkish brown, no sign of ocre or red ... and they do rust at the unpolished ends. Maybe gangue? Whatever it is, I suspect all the new age hematite is junk like this.

Another one to watch out for is necklaces etc etc made of Malachite. They look real and are more expensive then the rest of the junk. These streak clear, and do not fizz in acid. They look real enough, but are are coloured plastic.

The so called Moldavite has to be the worst when it comes to fake and prices being asked for it. Coloured glass for >NZ$60.

Chris. Johnson
NZ

A general comment about magnetism of not magnetite goethite/hematite/and other iron oxide/hydroxide compounds.

I came upon an unusual situation here in Arkansas several years ago. One of our geologists always carried a small but strong magnet with him to the field and everywhere he visited, he found in soils a magnetic fraction...almost always spherical beads appearing to be concretions from 0.5 to 2.5 mm in diameter. Scattered in soils across numerous localities in the state.

When confronted as to what they were and why they were there...at first I was at a loss except to say since they are in soils and appear to be concretions, they must be some iron oxide/hyroxide.

But then a couple of years later, a researcher sent me a book he had written on magnetism and lodestone...wow! did the light bulb brighten! Seems anywhere lightning hits the ground where there is soil, any iron compounds become locally magnetized or at least susceptible to being attracted to a magnet! And i began to take a look at lightning data and attempted to extrapolate that back 10,000 years for the ~ age of many soils....Wow! Hard to find a square foot that has not been struck!

I just mention this because the public is always bringing bits of magnetic soil etc in for me to identify. And I thought the commenters here might find that interesting as a source of conversion of normal magnetite into lodestone. Thanks

Just a maghemite component...?