Introduction

Magnetite on Albite, Cerro Huañaquino, Potosí Department, Bolivia 5cm tall
The name magnetite is apparently derived from the locality Magnesia, which borders on Macedonia. The ancient writers, Pliny and Nickander attribute the name to a person? named Magnes who on taking his herds to pasture found that the nails of his shoes and the iron ferrule of his staff stuck to the ground.

So far Mindat lists more than 9700 localities for magnetite and undoubtedly there are many more. Magnetite is one of the most abundant and commonly found oxides and is found under diverse geological conditions and sometimes in sufficient quantity to comprise an ore of iron. Magnetite is commonly found as grains in igneous rocks but most abundantly in the ferromagnesian types and at times as large segregated masses. Often these contain a lot of titanium in their composition due mostly to illmenite. Magnetite forms in the same conditions which form hematite and is usually if not always formed under conditions of high temperature. It it is found in the fusion crusts of meteorites and as dendritic forms in the mica of many localities and may be of secondary origin. It is also noted as a furnace product in slags and in sintered hematite ores. Brick, vitreous clay ware, and porcelain acquire a permanent magnetization parallel to the earths's magnetic field if magnetite crystals form during the firing. The largest deposits of magnetite are found in lens shaped masses in northern Sweden in Archaean rocks

A strong indicator that you may have magnetite is to see if it is attracted by a magnet and by checking its streak which is black. Maghemite, another strongly magnetic iron oxide, is brown to bluish black and can easily be confused with magnetite. However, unlike magnetite, it transmits light in thin splinters and has a brown streak. Hematite for which Magnetite is occasionally mistaken has a dark red streak and is not attracted by a magnet. Heating magnetite to 550 degrees C however alters the mineral to hematite and causes loss of its magnetic property. Magnetite alters to limonite and to hematite. Magnetite pseudomorphs after pyrite, chlorite minerals, anatase, talc, dolomite, chalcopyrite, siderite, and serpentine are known. Presumably all of these may be found not completely altered and containing the originative mineral and magnetite as well. So if you get a reaction to a magnet from a mineral, it may also not be a pure mineral, but partly magnetite. At some few localities, magnetite possesses polarity and this magnetite is given the variety name of lodestone. This means that the magnetite will act as a natural magnet. This natural magnetism can sometimes be enhanced by placing it in a strong magnetic field.

Magnetite crystals are most commonly found as octahedrons, but is also found in dodecahedrons with striated faces and more rarely as cubes. Sometimes octahedral forms of magnetite are altered to hematite and this is common enough that they are given the varietal name of martite (hematite, var. martite). Sometimes pure masses of twinned magnetite are found and when broken along its parting planes forms crystals that are sometimes mistaken for crystals of magnetite but are in reality just parting forms of twinned magnetite. The magnetite from Port Henry, New York example these. The cleavage of untwinned magnetite is not distinct.

The literature on magnetite and hematite is extensive and not something we want to go into here. Much of what is above was taken from Dana's/Ford text and Dana's system 7th edition, V1, P698-705 which has a nice summary of information about magnetite.

Historically, the most sought after crystals by collectors were perhaps those from Switzerland. Recently however the new find of good octahedral magnetites from Cerro Huañaquino, Bolivia and especially the new brilliant cubic magnetites from Balmat, New York, USA have displaced the Swiss specimens as the most desired. However, you can look at good examples of all of these and more in the picture gallery below and make up your own mind.

Afghanistan

Marki Khel, Sherzad District, Nangarhar, Afghanistan

Spin Ghar range, Nangarhar, Afghanistan

The one on the left above is from Marki Khel, and the one on the right from Speen Ghar. It would appear that both of these specimens are very likely from the same locality and at the very least we hope someone can help sort out what these two locality names represent when it comes to the specimens from them.

Argentina

Payún Matrú volcano, Altiplano de Payún Matrú, Agua Escondida District, Malargüe Department, Mendoza Province, Argentina

Specimens like this from Payún volcano are usually labeled Hematite after Magnetite and many more and much better examples are shown under Hematite in the Mindat Gallery and the Best Minerals Hematite article. It is possible that these specimens have still retained their magnetic character and that is why they are currently labeled magnetite. It is also possible, and perhaps even likely that these specimens have been mislabeled and are really now Hematite. Many collectors and some dealers really don't pay much attention to the accuracy of the labels they receive with their specimens or generate themselves and don't take the time to run even the simplest of tests on their specimens to determine if perhaps the labels may be in error. In fact they don't even know how. As time passes and you learn more and gain more experience you will see more and more errors on labels and will learn to look specimen labels with a more critical and analytical eye. We need more of this kind of person here on mindat to help clean up the mistakes and errors that exist here on Mindat.
"Although these specimens are usually labelled "Payun" or "Payun Matru" volcano, this is actually in a rather extensive volcanic field with dozens of vents, and exactly which fissures these crystals came from has understandably not been revealed by the prospectors who dig them, and there are at least two localities for them in this area, so "Payun Matru region" or just "Altiplano de Payun Matru" might be a more honest locality designation, leaving off the volcano name. As is obvious from the crystal habits, these started out as magnetite, although the majority have oxidised to hematite and should now be labelled "hematite pseudomorphs after magnetite". A minority are still magnetite, or only partially replaced. Magnetite and hematite crystals, often skeletal, deposited from the gas phase in volcanic fumaroles by hydrolysis of iron chloride vapour are fairly common in high-temperature volcanic fumaroles worldwide, but these argentine examples are by far the largest and finest fumarolic magnetites known." - Alfredo Petrov, 2010.

Australia

Mud Tank Zircon Field, Alcoota Station, Central Desert Region, Northern Territory, Australia

This is a popular collecting spot, mostly for large zircon crystals, in a carbonatite. It was being mined for Vermiculite recntly, with collectors allowed to fossick on the dumps still. The magnetite crystals can be large, but are seldom completely intact.

Biggenden Mine, Mount Biggenden, North Burnett Region, Queensland, Australia

This site was a large magnetite mine, in a skarn deposit. It was a popular spot for collecting until the mine closed some (20?) yrs ago, and specimens are rarely seen now.

Sitting Bull area, Arkaroola Region (Arkaroola Wilderness Sanctuary; Arkaroola Station) , North Flinders Ranges, Flinders Ranges, South Australia, Australia

A popular collecting area with various small iron, copper, fluorite and uranium deposits related to granite intrusions, but good specimens are rarely seen.

Kara No. 1 Pit, Kara Mines, Hampshire mining district, Burnie City, Tasmania, Australia

An operating open-cut mine, located 40 km south of Burnie in northwestern Tasmania, producing magnetite and minor scheelite. It is the only presently operating mine in a series of related skarn deposits associated with Devonian granites intruding Ordovician limestones. The pit contains a zoned magnetite-andradite-hedenbergite-vesuvianite-epidote skarn, which contains minor scheelite and molybdenite and calcite veins with various Cu, Pb, As, Zn, Bi sulphides, fluorite and some Be minerals. Famous for excellent andradite specimens and many other interesting minerals. Magnetite is very common, often in well formed dodecahedral crystals, to about 5cm, but are typically a little dull in lustre. They may be coated in other crystallised minerals, including bavenite, fluorite, calcite, andradite, epidote, tremolite and helvite-danalite.

Austria

Totenkopf (incl. Lower Riffl glacier), Uttendorf, Zell am See District, Salzburg, Austria

Furtschaglkar, Finkenberg, Schwaz District, Tyrol, Austria

Azerbaijan

Dashkesan Co-Fe deposit, Dashkasan, Dashkasan District, Azerbaijan

Bolivia

Cerro Huañaquina, Yocalla Municipality, Tomás Frías Province, Potosí, Bolivia

As you head north out of Potosi, the main highway for a distance passes by Cerro Huañaquino. If you look up at that point you can see little prospects scratched on the side of the mountain a few hundred feet up, and this is the locality that has produced all the recent specimens of Magnetite from Bolivia. Several thousand of them have been produced and sold to the collector market. Some of the specimens are surprisingly good and may rank among the best Magnetites found anywhere. On many specimens the magnetite crystals are growing on tiny crystals of albite.

Brazil

Diamantina, Minas Gerais, Brazil

Canada

Hampton, Annapolis Co., Nova Scotia, Canada

John Sinkankas notes in his Mineralogy that small, beautifully crystallized magnetite crystals occur in the Triassic trap rocks of Kings and Annapolis counties.

Amethyst Cove (Captain Kidd's Cove), Kings Co., Nova Scotia, Canada

Faraday Township, Hastings County, Ontario, Canada

John Sinkankas notes in his Mineralogy that a single crystal from this locality weighed in at more then 400 pounds.

Chile

El Laco Fe deposit, San Pedro de Atacama, El Loa Province, Antofagasta, Chile

Cuba

Juragua Iron Company Mines, Firmeza District, Santiago de Cuba Province, Cuba

France

Puy de Wolf (Puech de Voll), Firmi, Villefranche-de-Rouergue, Aveyron, Occitanie, France

Germany

Michelsberg Quarry, Katzenbuckel, Eberbach, Rhein-Neckar-Kreis, Karlsruhe Region, Baden-Württemberg, Germany

The Magnetite (Titanomagnetite) from Katzenbuckel are crystals up to 3cm but most of the crystals found were only a few mm. At this location the magnetite crystals are frequently oxidized to Maghemite. They are still magnetic, but the streak changes from black to brown. If etched with cold 30 % HCl this pseudomorphed crystals give a white residue of Leukoxene ( Anatase) while with the real Magnetite the black Ilmenite inclusions remains. The locality is of the European Province with unusual peralkaline dyke rocks. This location was first metioned by Leonhard in 1822 for Nepheline and is located about 35 km E of Heidelberg. With a very long list of papers until today. A milestone of petrography/ petrology research ( Rosenbusch). The quarries were operated from about 1900 to 1974, the locality is now a geotop. The crystals are not free standing but found covered by natrolite, but the crystals are easy to clean because of alteration of the rock. The magnetite specimens were abundant for a short time (1966 to 1973). Since that time collecting is almost impossible as the zone that was productive of the magnetite crystals is flooded. I think only a small number has been distributed, but one of the best magnetites in Germany. There are better specimens than the one pictured here

Silberberg Mine, Bodenmais, Regen District, Lower Bavaria, Bavaria, Germany

Mendig, Mayen-Koblenz, Rhineland-Palatinate, Germany

Callenberg, Zwickau District, Saxony, Germany

Italy

San Vito Quarry, San Vito, Ercolano, Mount Somma, Somma-Vesuvius Complex, Naples, Campania, Italy

Malenco Valley, Sondrio Province, Lombardy, Italy

Lanterna Valley, Malenco Valley, Sondrio Province, Lombardy, Italy

Dossi di Franscia, Franscia, Lanzada, Sondrio Province, Lombardy, Italy

Traversella Mine, Traversella, Metropolitan City of Turin, Piedmont, Italy

Brosso Mine, Calea, Lessolo, Metropolitan City of Turin, Piedmont, Italy

Japan

Kuryu mine, Nagano Prefecture, Japan

Mexico

Santa Eulalia Mining District, Aquiles Serdán Municipality, Chihuahua, Mexico

Cerro de Mercado Mine, Victoria de Durango, Durango Municipality, Durango, Mexico

The magnetites from this locality are not particularly outstanding, but when they occur with sharp yellow sometimes transparent apatite crystals, I must admit that I find I become more interested in them.

Morocco

Jebel Bou-Agrao, Amersid, Aït Oufella Caïdat, Midelt Cercle, Midelt Province, Drâa-Tafilalet Region, Morocco

Imilchil, Imilchil Caïdat, Imilchil Cercle, Midelt Province, Drâa-Tafilalet Region, Morocco

Mozambique

The only locality we have for this specimen is Mozambique, but the thing is huge and a deposit that produces things like this must produce other note worthy specimens. I hope someone can eventually tell us more about this locality and its specimens. The crystals on this specimen must be nearly as big as your fist and the thing must weigh well over 100 pounds.

Namibia

Erongo Mountains, Karibib Constituency, Erongo Region, Namibia

Norway

Hattfjelldal, Nordland, Norway

Auen Quarry (Blue Pearl Quarry), Auenlandet, Porsgrunn, Telemark, Norway

Auen is one of the many larvikitie quarries in this area. Larvikite is quarried as a dimension stone and is widely used as countertops and claddings. The commercial grade larvikite consist predominantly of blue or black schillerizing feldspar.
The larvikite was formed as igneous plutons during Permian (+/- 300mill years ago) rifting in the Oslo graben in southeastern Norway. These igneous plutons are host to numerous alkaline pegmatites carrying many rare minerals.

The magnetite at Auen was found in one of these pegmatites in 1996. The actual pegmatite was severly altered, with a clay mineral, albite covered microcline and magnetite as main minerals. Small zircon, molybdenite sheets and a yellow, transparent mineral was present as accessory minerals. Most of the magnetite was partly altered to hematite
The magnetite crystals reached almost 10 cm across and often had quite complex crystal shapes. The best specimen I found was a 15cm wide cabinet specimen consisting of three intergrown magnetite crystals. This specimen is now on loan to Agder Naturmuseum in Kristiansand. The magnetite was abundant in this material, and several truck loads of material were available just after the pegmatite was exposed, and magnetite could still be found in the quarry a few years after the initial exposure of material.

Pakistan

Sapat Gali, Naran, Kaghan Valley, Mansehra District, Khyber Pakhtunkhwa Province, Pakistan

Magnetite crystals growing with gem grade peridot crystals? Every collector would love to have one of these. But the association was not common and for every thousand peridot crystals there may have been one specimen with this association.

Poland

Miedzianka, Gmina Janowice Wielkie, Karkonosze County, Lower Silesian Voivodeship, Poland

Russia

Olga Bay, Olginsky District, Primorsky Krai, Russia

Kovdor Zheleznyi Mine, Kovdor Massif, Kovdorsky District, Murmansk Oblast, Russia

Akhmatov mine, Magnitka, Kusinsky District, Chelyabinsk Oblast, Russia

South Africa

Aggeneys, Khâi-Ma Local Municipality, Namakwa District Municipality, Northern Cape, South Africa

Spain

Milucha Mine, Burguillos del Cerro, Badajoz, Extremadura, Spain

Sweden

Nordmark Odal Field, Filipstad, Värmland County, Sweden

Switzerland

Binn Valley, Valais, Switzerland

Lärchultini, Binn, Goms, Valais, Switzerland

>

USA

Perovskite Hill, Magnet Cove, Hot Spring County, Arkansas, USA

At one time magnet cove was famous for specimens of massive magnetite specimens that acted as natural magnets. They were rated in quality by the size of the nails they could pick up. The 16 penny grade would pick up 16 penny nails and the ten penny quality would pick up the larger ten penny nails (those that sold ten for a penny). The most highly sought after material was the spike grade material that would actually pick up a small railway spike.

Christie Mine (Christi Mine; Christy Mine; Christie Asbestos; Coalinga Asbestos), Wright Mountain, Fresno County, California, USA

New Idria Mining District, San Benito County, California, USA

Santa Rita Mine (Union Carbide Nuclear; Santa Rita Asbestos Mine; Joe 5 pit; Joe 7-5 Mine; KCAC Mine), Santa Rita Peak, San Benito County, California, USA

Spring Mountain Mining District, Lemhi County, Idaho, USA

Laurel Hill, Secaucus, Hudson County, New Jersey, USA

At Laurel Hill, magnetite veins are common. Perfect specimens are not easy to come by, due to weathering and brittleness. Good specimens are obtained, when vein walls are composed of soft chlorite. Excellent splendent crystals were observed suspended as individuals and groups in the mountain leather variety of actinolite. Their color coal-black; crystallizing as octahedrons or penetrating (spinel) twins; up to 3 cm on an edge and associated with albite, sphalerite, pyrite, bornite, chalcopyrite, allanite, epidote, orthoclase, and quartz.

Sterling Hill, Ogdensburg, Sussex County, New Jersey, USA

Continental No. 2 Mine, Fierro, Hanover-Fierro Mining District, Grant County, New Mexico, USA

Republic Mine, Empire Zinc Mine, Hanover-Fierro Mining District, Grant County, New Mexico, USA

Jones District, Socorro County, New Mexico, USA

Port Henry, Mineville Mining District, Essex County, New York, USA

These were at one time quite common among collectors in the north eastern part of the United States, but now are seldom seen. The bottom three images show not terminated crystals of magnetite, but rather parting forms that have been broken from massive twinned magnetite.

Tilly Foster Iron Mine, Town of Southeast, Putnam County, New York, USA

The magnetite and clinochlore specimen pictured above is about as good as this association gets from this mine.

Empire State No. 4 Mine, Balmat, Balmat-Edwards Zinc Mining District, St. Lawrence County, New York, USA

The magnetite specimens from this mine have been around for a few years, but because of their brilliance and relatively cubic shape, they have a new standard of quality that other localities find difficult to match. The best from this locality are truly world class for the species.

Grace Mine, Morgantown, Berks County, Pennsylvania, USA

French Creek Mines, Saint Peters, Warwick Township, Chester County, Pennsylvania, USA

There are better specimens of magnetite than the one pictured here and we will add one or more of them as soon as possible.

Carlton Quarry, Chester, Windsor County, Vermont, USA