(From the old chronicles.)
From the dossier:
magnetite - a mineral, ferrous oxide, is one of the constituents of iron ore. Hardness 5.5-6.0 on the Mohs scale, density 4.9-5.2 g / cm3, metallic luster. Other names: magnetic iron ore, herculean stone (obsolete) 
A black-colored mineral with a bright metallic luster, which has strong magnetic properties, is. People have known about magnetite for a long time. The Chinese knew him in the 6th century BC. and used it as a compass, and the philosopher Plato in his works talks about a wonderful magnetic stone, which not only attracts iron objects, but also transfers its power to them (magnetizes), so that they also begin to attract iron. According to the legend, magnetite got the name “magnet” (from the Greek magnetis) after the name of the mythical Greek shepherd Magnes, whose shoes with iron nails and the iron tip of a staff constantly adhered to the surrounding stones. However, it is more likely that this name comes from the name of the ancient city of Magnesia in the territory of modern Turkey. There was a mountain not far from the city, which was often hit by lightning. Mount Magnetic in the Urals, consisting almost entirely of magnetite, is also known for this property. The Thousand and One Nights tales mention Mount Zimir in Ethiopia, which pulls all the nails and iron pieces out of the ships.
It was Plato who argued that Euripides in his dramas called this stone "the stone from Magnesia." It was called a magnet until the Middle Ages, then the name magnetic iron ore appeared, and in 1845 - the modern name - magnetite.
Magnetite usually forms beautiful octahedral crystals; the crystals grow together into beams, form druses and brushes, and have characteristic shading on the edges. It can also be found in placers in a rounded form; even spherical formations of magnetite are known - natural magnetic balls. Accumulating in coastal placers, magnetite forms the so-called black sands. This mineral is the second most important after the iron ore mineral, contains more than 70% of this metal, the rest is impurities of titanium, chromium, magnesium, manganese, nickel, vanadium, aluminum. Very beautiful crystals come from Switzerland; the largest deposits are located in Norway, Russia (Ural, Kursk Magnetic Anomaly), USA (Adirondack Mountains, Magnet Cove, etc.), in Ukraine (Krivoy Rog basin). Magnetite is also mined in Germany, Romania, South Africa.
The Iron Age, which, by the way, still lasts, is the Age of Magnetite. But more than a source of iron, magnetite has attracted people at all times for its amazing properties of attracting iron objects. This immediately gave rise to associations and comparisons with human relations, so Pliny even distinguishes between types of magnetite: male and female, which attract and repel objects made of iron. Of course, magnetite was not called a magnet everywhere. In China he was known under the name Chu-shi, in France - as Aiman, in India he was called Thumbaka, in Egypt - the Ora bone, in Greece - the Herculean stone, and in England since the 16th century and the USA it is still called the lodestone (lodestone ). Loud translated from Old English means "way", that is, a stone that shows the way. This name was given to magnetite by sailors for the property of magnetized iron arrows to point to the south. However, many names are translated as "loving", "lover" - because of his "attraction" to iron. We are also talking about people who are attracted to each other: "pulls like a magnet."
In Europe and Asia, lumps of magnetite have been used equally successfully as a natural compass. They were hung on a string or fixed on a plank floating on the water: one side of the stone always pointed to the south. Travelers were the first to take advantage of this property. The old French name for magnetite "marinette" is known, in which the sea roots are clearly traced. In the Chinese chronicles there is information about the use of a magnetic needle on ships in the III-IV centuries. There is also earlier evidence of people's acquaintance with the properties of magnetite and the earth's magnetic field in general. The ancient Olmecs, who lived in Central America, carved out of huge blocks of magnetite the figures of the so-called "fat boys" - symbols of well-being, satiety and prosperity. The sculptures are over three thousand years old, but they are made in such a way that the magnetic field exits exactly from their fat bellies. They still stand in the square of the city of Democracy in Guatemala.
The Italians erected a monument to Flavio Gioia in Naples, whom they believe to be the inventor of the compass. A beautiful legend tells a story 
the love of the jeweler Flavio Joya and Angela, the daughter of a wealthy fisherman. Flavio was not rich, besides, he did not know the sea, and Angela's father Domenico wanted to marry the girl off to a sailor. He set a condition: if Flavio learns to swim in a straight line in the fog and at night, then he can marry Angela. Of course, this was impossible, but Flavio, thanks to his profession and close acquaintance with stones, knew about the property of magnetite to point to the south. He built a primitive compass so that one could navigate the sea, and a month later he married Angela. And the sailors now went to sea with a compass, and this happened in 1302.
Beautiful as it is, it’s just a legend. The European compass dates back to the 12th century. And the Chinese are the first to invent this device using magnetite. But Italians stubbornly believe in a beautiful story and in the "inventor of the compass" Flavio Gioya. In the end, this story could very well have happened.
But what really happened was the use of magnetite in construction. And in this regard, there are many stories of ancient historians, records in the annals and just legends. For example, the ancient Chinese used the chu-shi stone in the construction of pavements, as well as magnetic gates, through which not a single person with a weapon could pass - this is how the inhabitants discovered ill-wishers. Emperor Huang Ti won a significant victory three thousand years ago thanks to magnetite. His court craftsmen made carts on which 
rotating stone figures with an arm extended forward. The hand always pointed to the south, thanks to which, in the fog, the emperor was able to attack the enemy from the rear and defeat him.
The legendary chapel of Mohammed with a magnetic vault is also known, under which an iron chest with the prophet's ashes hovers, but the Europeans never managed to see it. Pliny speaks of the construction of the temple of Arsinoe (wife and sister of Ptolemy, king of Egypt in the 3rd century BC). It was assumed that the iron statue of Arsinoe would hang from the ceiling, but the Alexandrian architect Chinokrat (or Timokhares) died before he could finish building the temple. In the same Alexandria there was a temple of Serapis (the combined cult of Zeus and Osiris), in which the statue of the god flew up to the ceiling.
Of course, all these phenomena in ancient times seemed miracles, magic and sorcery, so many charlatans appeared who claimed to have "magical" power, the ability to heal and other properties, proving this with the help of magnetite. In ancient Greece, wandering magicians staged performances with iron rings hanging under each other and not connected in any way.
However, if we talk about the healing properties of magnetite itself, then it has them due to its magnetic field. Like a magnet capable of 
free from accidentally swallowed iron, magnetite is mentioned by Avicenna in the "Canon of Medicine": "It is given to drink in wine to the one who swallowed iron filings, and to the one who has iron slag stuck in his stomach; magnetite pulls out and accompanies them when they leave. " Even in modern medicine, probes with a magnet at the end are used to extract iron objects from the intestines.
In addition, there are medicinal jewelry that acts on the body from the outside. It can be beads, rosary, bracelets, key rings, pendants, earrings, and magnetic balls are used for massage. Their field is so strong that two balls can be attracted "through" the palm, not supported by anything. magnetite is used for disorders of the musculoskeletal system, for stroke to accelerate rehabilitation; with low blood pressure, fatigue and chronic exhaustion of the body.
Magnetite balls are used for anti-cellulite massage; children are happy to play with balls, which, being attracted to each other, interlock in a ring, chain and other figures; it allows you to develop your hands. Foot massage with magnetite balls relieves fatigue, 
swelling. But, besides medicinal, jewelry with magnetite also has an aesthetic effect; Magnetite c cabochons with a natural combination of strokes of silver and gold shine look very beautiful in jewelry. Black beads of pure magnetite are used to make beads and beads.
It should not be forgotten that wearing magnetite jewelry should be dosed, and the use of magnetite as a remedy has a number of contraindications. The massage should not last longer than 30-45 minutes, and exercises with balls in general should not last longer than three hours a day. Contraindications in the use of magnetite are similar to those for intensive massage and acupuncture: infections, fever, wounds, burns, eczema, etc., bouts of hypertension, swelling, acute pain. During pregnancy, you should also not use magnetite products. It is worth remembering that the magnetic field negatively affects the operation of mobile phones, computers and other equipment, and iron objects, being near magnetite, can become magnetized.
magnetite is considered a stone that stimulates the imagination, a companion of innovations, therefore it is recommended as a talisman for inventors, engineers, and travelers. He patronizes Aquarius and Capricorns, who will help them see new things in life. The rest of the zodiac signs can also wear magnetite jewelry and use balls to relax.
It is already impossible to imagine the modern world and human civilization without magnetite. Thanks to him, one of the greatest inventions of all time was created - the compass. This means that long voyages and travels to unfamiliar lands became possible, which led to the great geographical discoveries. And all this is thanks to a piece of black stone. In our age of satellite navigation systems and new materials, magnetite is still in demand, including as useful and beautiful jewelry, which is a symbol of the inquisitiveness of the human mind and the generosity of nature.
/ mineral Magnetite
Magnetite is a mineral, iron oxide (Fe2 + and Fe3 +), spinel group. FeO - 31; Fe 2 About 3 - 69; impurities of titanium, chromium, magnesium, manganese, nickel, vanadium, aluminum are common. Magnetite is one of the most abundant oxide minerals and is found in a wide variety of geological formations. Mineral magnetite is magmatic (in rhyolites, granites, trachytes, syenites, andesites, diorites, gabbros, basalts, pyroxenites, peridotites, olivinites, in pegmatites), hydrothermal and metamorphic - in skarns; in metasomatites - (pyroxene-amphibole-magnetite, apatite-phlogopite-magnetite, magnetite-phlogopite-calcite, magnetite-calcite); in talc-chlorite, talc-magnetite schists and serpentinite; in the regionally metamorphic. g. n, in placers, rarely sedimentary. The mineral magnetite has strong magnetic properties and is attracted by a magnet. Behavior in acids: difficult to dissolve in HCl. The powder dissolves noticeably. Large industrial deposits of the mineral magnetite in Russia are located in the Kursk Magnetic Anomaly, in the Murmansk region (Kovdor deposit), in the Urals (Magnitogorsk). The mineral magnetite is the main ore for iron. This stone is not used very often in the jewelry industry. Usually, beads, bracelets, and rosary beads are made from it. Magnetite is suitable for making both women's and men's jewelry. In the chemical industry, this breed is used to obtain vanadium and phosphorus. Magnetite is also widely used today. This stone is especially popular in China. The first mentions of magnetite are found in ancient Greece. The stone was in great demand during the Middle Ages. Several decades ago, in the states of Asia and Europe, this breed was used to establish the direction of movement, i.e. the stone acted as a compass. Evidence has been found that this mineral was used by the ancient Olmecs - tribes who lived in Central America. They made figurines from stone, which acted as various symbols. Many peoples have used magnetite to make mirrors.
Magnetite forms a solid solution with jacobsite Mn2 + Fe3 + 2O4 and magnesioferrite MgFe3 + 2O4.Other names (synonyms):
Varieties:
Chemical composition
Magnetite is the main component of oxide iron ores - ferruginous quartzites, magnetite skarn and carbonatite ores, as well as magnetite "black sea sands".The main diagnostic signs
Place of Birth
Deposits of ferruginous quartzites are known in Ukraine (Kryvyi Rih), magnetite is mined from skarns in Azerbaijan (Dashkesan deposit). Also deposits of the mineral magnetite are known in Italy, Sweden, Greenland, Brazil, USA, South Africa, Canada, etc.Application
Stone history
tell about an error in the description
Mineral properties
| Colour | iron black, sometimes with blue tarnishing |
| Line color | black |
| origin of name | According to Pliny the Elder, from the Greek. Magnes is the name of the legendary shepherd who first found a natural magnetic stone that attracts iron in the city of Ida (Greece). Or in the area of Magnesia in Macedonia |
| IMA status | valid, described for the first time before 1959 (before IMA) |
| Chemical formula | FeFe 2 O 4 |
| Shine | metal matt semi-metallic |
| Transparency | opaque |
| Cleavage | not visible |
| Break | conchoidal uneven |
| Hardness | 5,5 6 |
| Thermal properties | P. tr. does not melt. In an oxidizing flame, it first turns into maghemite, then into hematite, losing its magnetic properties |
| Typical impurities | Mg, Zn, Mn, Ni, Cr, Ti, V, Al |
| Strunz (8th Edition) | 4 / B.02-20 |
| Hey "s CIM Ref. | 7.20.2 |
| Dana (8th Edition) | 7.2.2.3 |
| Molecular weight | 231.54 |
| Cell parameters | a = 8.397Å |
| Formula units (Z) | 8 |
| Unit cell volume | V 592.07 ų |
| Twinning | Common by (111), with the same face as the composition face. Twins flattened parallel to (111) (common spinel law twins), or as lamellar twins, producing striae on (111). Twin gliding, with K1 (111), K2 (111). |
| Point group | m3m (4 / m 3 2 / m) - Hexoctahedral |
| Space group | Fd3m (F41 / d 3 2 / m) |
| Separate | by (111) distinct, also reported separately by (001), (011), (138). |
| Density (calculated) | 5.2 |
| Density (measured) | 5.175 |
| Internal reflexes | absent |
| Refractive indices | n = 2.42 |
| Maximum birefringence | δ = 0.000 - isotropic, does not have birefringence |
| Type of | isotropic |
| Optical relief | very tall |
| Color in reflected light | gray with a brownish tint |
| Allocation form | crystals of octahedral, less often rhombic dodecahedral habit with simple shapes (100), (111), (110), (211), (210) and characteristic diagonal shading on the faces (110), crystalline intergrowths and aggregates, druses, brushes, dense granular and solid masses, dissemination in igneous rocks, individual grains in placers. Also known are spherulites, kidney-shaped aggregates, oolites, pseudomorphs of magnetite over hematite (musketovite), chrysotile-asbestos, perovskite and other minerals. |
| Classes on taxonomy of the USSR | Oxides |
Magnetite, also known as magnetic iron ore or ferroferite, is a mineral from the class of oxides that is widespread in nature. It earned its name for its ability to attract iron due to the octandric shape of the crystals, which have twice as many metal cations in one position as in the other. There is also a theory that magnetite was named after Magnes, the shepherd who discovered it.
Description and formula of the mineral
Magnetite formula: FeO (31%) Fe2O3 (69%), may include other chemical elements. This mineral is the most iron-rich oxide. The metal content is within 71%, although there are also purer forms.
Other characteristics:
- the color of this magnetic ore is iron black;
- hardness is 5.5-6;
- shine metallic, metallic and matte;
- the mineral is opaque;
- has magnetic properties;
- the density is 4.9-5.2 g / cm ³;
- does not have perfect cleavage;
- conchoidal fracture.
Magnetite of mineral nature occurs in the form of individual crystals (rhombic dodecahedrons, octahedrons, etc.) with disseminations, loose or granular masses, placers.
Crystals are found overgrown or ingrown. The system is cubic.
Distinctive characteristics: magnetic iron ore can be easily recognized by its appearance, metallic black color and magnetic properties.
Varieties of ferroferite
Magnetite has several variations. They differ from each other in form and composition:
Origin and formation
Magnetite is common in hypogenic conditions. It is found in a wide variety of rock types. and in other deposits (hydrothermal, for example). Magnetic iron ore is formed in the contact zones of magmas of granite origin, as well as diorite and syenite composition with limestone content. In such basic (less often - in neutral or acidic) deposits, ferroferite occurs in the form of continuous masses or inclusions in the parent rock.
It often forms stratal deposits. The origin of magnetic iron ore is associated with the differentiation of magma. Under the influence of pressure and temperature at great depths, metamorphism of previously surface iron compounds occurs.
In the form of a placer, magnetic iron ore is found mainly in surface conditions.
Largest natural locations
Russia has the largest reserves of magnetite: more than half of the world's iron ore reserves are located on its territory. Brazil is in second place.
Magnetic Mountain is located on the eastern slope of the Southern Urals on the left bank of the Ural River. Its composition is almost entirely composed of ferroferite and has been used for the extraction of raw materials for many years. Up to 1 million tons of iron ore are mined annually.
Within the Kursk, Oryol and Belgorod regions the world's most powerful iron ore deposit is located, which in another way is called the Kursk magnetic anomaly.
One of the largest iron ore deposits is located in the El Mutun Mountains, near Puerto Suarez, Bolivia.
Application in various fields
Some people believe that magnetite has some magical properties. For example, it played the role of a stone endowed with magic, which was used by sorcerers and alchemists. It was used as a protective stone from enemies, which is carried with them or kept in the house. Magnetite contributes to the disclosure of new abilities and creativity, adjusts to the working mood, is a symbol of innovation.
In modern medicine, the use of magnetite in wellness procedures in the treatment of the vegetative and vascular systems is widespread and, as the data say, it is quite successful.
Magnetite is an unusual stone that has the property of magnetism, incredible for nature. In addition, its medicinal and magical properties are known.
The origin of magnetite is quite common. The mineral is formed as a result of the interaction of granite, diorite and syenite rocks. It is present in such rocks in the form of homogeneous or disseminated masses. This origin is important for the industry.
Deposits of this stone have an acidic or neutral environment and arise as a result of the dissolution of igneous rocks. The origins of the stone are formed by different rocks. Magnetite is often localized in pyroxenites and gabbro. The mineral looks like bedded deposits or individual inclusions in other minerals.
The rock is formed by metamorphism of ferruginous compounds localized on the surface. Magnetite and hematite are formed in the middle zones.
In the form of heterogeneous deposits, it occurs on the surface layers. In the presence of sulfide compounds, the stone is converted to hematite or limonite. After the destruction of the rock in magnetite, the formation of sulfuric acid occurs, the environment of which provokes the processes of destruction of magnetite.
Formula
Magnetite is a mineral made from iron ore. Magnetite can be described by a chemical formula, like any other naturally occurring object. Chemical formula - FeO × Fe2O3.
This mineral is localized in various formations and is metamorphic, magmatic and sedimentary.
The crystals are octahedral, which is due to the metallic bond between different types of iron cations. Due to this feature, it is able to form a magnetic field and attract iron. Chemical properties are poorly expressed.
Mining locations
The largest volume of deposits is located in Russia and Brazil. Extraction is also carried out in the USA, Canada, India and other countries in small quantities.
The largest field in terms of area is the Kursk Magnetic Anomaly, stretching from Smolensk to Rostov Oblast. The reserves of this place are several times higher than all other deposits combined.
Deposits are popular in the Urals, Kruglogorsk, Kusinsk and Pervouralsk. In the Urals, a new place of deposits was recently discovered - Maly Kuibas, which is located near the city of Magnitogorsk.
In Kazakhstan, a large deposit is the basin of the Kustanai region. Here the volume of magnetite exceeds the deposits in the Urals.
Related video: Magnetite sample
Physical properties
The stone has a deep black color. It has a pronounced metallic luster, but there are also matte rocks. Magnetite exhibits the properties of a weak base, slowly dissolving in water.
The mineral is not transparent. The density of magnetite is quite high and ranges from 5.5 to 6 on the Moss scale. Magnetite has pronounced feromagnetic properties. This property contributes to a change in the correct operation of the compass, which helps to detect deposits of material.
Magnetic properties disappear when heated above 580 degrees Celsius. Upon cooling, this property is restored. Magnetite has fractures and an uneven surface.
Magical properties
Magnetite has been known to people since ancient times, and its field of application was wide. The stone was very popular due to its properties. Due to the lack of knowledge in physics, people could not correctly explain the nature of the phenomenon of magnetism. For this reason, magical properties were attributed to him and was sometimes used for medicinal purposes. In those days, the stone was considered a strong talisman and amulet capable of protecting against the effects of evil forces.
Sorcerers made their wands from magnetite and outlined figures during rituals. The stone promotes the manifestation of a person's magical abilities and the development of talents. According to the notes of eyewitnesses who have come down to our days, it is known that Alexander the Great gave out a stone to each of his soldiers for protection from evil forces. Adherents of occult cultures still use this stone in their practice, believing in closed magic in magnetite.
Zodiac signs
Magnetite is not widely popular in astrology, but it is compatible with people of almost all signs. But it is believed that it is desirable for the signs of Earth and Air. Therefore, it can be worn by Capricorns, Aries and Skopions. It is on these signs that he influences more beneficially.
Medicinal properties
The unusual properties of magnetite explains its use in medicine. Well-known doctors of ancient times tried to treat many diseases of various systems with magnetite. Dioscorides advised people who are prone to depressive states to always have this iron ore with them. Avicenna described its medicinal properties in diseases of the digestive system. Albertus Magnus noticed that if you wear a bloodstain on your left hand for a long time, you can recover from psychotic and hysterical conditions.
Philosophers of the classical Greek period mentioned him in their writings. For a long time, the mineral was prescribed for oral administration, but it was found later that it provokes severe pains of various localization. Mesmer succeeded in therapy with this stone. He studied its hypnotic and magnetic properties. The Commission on Minerals found that the use of the stone is effective only for diseases of a nervous nature.
Currently, the stone is used in medicine for treatment by exposure to a magnetic field. This field has a beneficial effect on some diseases, facilitating their treatment.
Useful action of the stone:
- anti-aging effect, which is noticeable in laboratory studies on animals;
- antibacterial action;
- removal of convulsive conditions;
- wound healing with magnetophoresis exposure;
- promotes fusion of damaged structures;
- relieves discomfort with varicose veins;
- facilitates the course of Parkinson's disease;
- helps with polio and respiratory diseases.
How to distinguish from a fake
This mineral does not belong to the high price segment, which makes counterfeiting it not entirely profitable. Magnetite can often be confused due to its external similarity with hematite. In nature, they have a similar meaning and are able to replace each other. To distinguish a genuine stone, it is necessary to test it for a magnetic field, it is this difference that distinguishes it from hematite. Only magnetite in nature is capable of exhibiting magnetic properties - this is its difference.
Output
If you prefer unusual stones, then magnetite should be in your collection. The stone will have a beneficial effect on your health, surprise with its brilliance and magnetic properties, and all this at a low price.
Magnetite iron mineral, formula, chemical composition, description, photo, properties, ore, where to find and how it is mined, deposits, origin
Synonyms: magnetic iron ore.
Magnetite - chromite group
Magnetite an ore mineral used by man since ancient times.
origin of name
The origin of the mineral's name is unclear. The name, apparently, was given for the area (Magnesia) bordering on Macedonia. It is also possible that the origin of the name is connected with the legends of Magnes, the shepherd who first found this mineral, noticing that the iron tip of his staff and the nails of his boots adhered to the ground.
Magnetite Formula
Octahedral magnetite crystals PhotoFe 3 + (Fe 2+ Fe 3+) O 4, abbreviated formulas are also used: Fe 2+ Fe 3+ 2 O 4 - FeFe 2 O 4 or even - Fe 3 O 4.
Chemical composition
Magnetite- the most iron-rich oxide. FeO - 31.03%, Fe2O3 - 68.97%. Fe content - 72.4%. It is usually relatively pure in composition.
Other members of the magnetite series:
- Magnesioferrite -MgFe 2 O 4
- Franklinite - ZnFe2O4
- Jacobsite - MnFe2O4
- Trevorite - NiFe 2 O 4
- Ulwöspinel - TiFe 2 O 4
Varieties
1. Titanomagnetite - it would be more correct to write Ti-magnetite, i.e. titanium magnetite, which contains TiO2 (up to several percent), existing at high temperatures in the form of a solid solution of ulvöspinel Fe2 + (Fe2 + Ti4 +) O4 in magnetite, ulvöspinel and precipitates in magnetite matrix during the decomposition of the solid solution, usually oxidizing further to ilmenite. Many titanomagnetites are characterized by the presence of a significant admixture of coolsonite, which makes such varieties an industrially important source of vanadium.
2. Coulsonite - vanadium magnetite - Fe2 + V3 + 2O4 (abbreviated as (Fe, V) 30 4) contains up to 4.84% vanadium.
3. Cr-magnetite with the content of Сr2О3 (up to several percent).
4. Occasionally meet differences rich in MgO (in Mg magnetite up to 10%), Al2O3 (15%), etc.
5. Maghemite - (initial letters of words magnetite and hematite). A relatively rare naturally occurring ferromagnetic iron oxide γ Fe 2 O 3 of a cubic system.
Crystallographic characteristic
The system is cubic; hexaoctahedral c. with. O h 7 Fd3m, Z = 8 a 0 = 8.374 A.
Magnetite at - 178 ° becomes rhombic, a 0 - 5.91, b 0 = 5.945, c 0 = 8.39
The crystal structure is an inverted spinel structure. B A B O 4
The structure is reverse spinel, since half of the ferric atoms are located in the tetrahedral voids of the closest cubic packing, while the ferrous atoms together with the other half of the ferric atoms are located in the octahedral voids of the structure. Therefore, the formula for magnetite should be written as follows: Fe3 + (Fe2 + Fe3 +) O 4.
The form of finding the mineral in nature Photo
Crystal Form
According to the structure, magnetite crystals are almost always octahedral, but they are also known
and rhombic dodecahedral.
Magnetite. Octahedral crystals in shale The (110) faces are often covered with strokes parallel to the long diagonal of the rhombuses. In basalt glass under a microscope it is set in the form of nanoparticles of dendrites.
Twins in (111).
Aggregates
For the most part, it is found in continuous granular masses or in the form of inclusions in igneous, mainly basic rocks. Druses of crystals can be found in the voids. Oolites are found in sedimentary rocks.
Under natural conditions, the oxidation of magnetite very often occurs - the process of martitization, sometimes leading to complete pseudomorphs of hematite over magnetite (martite). The reverse process, known as musketisation, occurs when hematite is reduced.
Physical properties
Crystal optical properties
The color of magnetite is iron-black to brown, sometimes with a bluish tarnishing on the crystals.
The line is black (powder color).
Metallic or semi-metallic luster.
Opaque. Only the finest fragments transmit light; n = 2.42.
Mechanical
Origin
Magnetite- the most common oxide in hypogenic conditions.
Unlike hematite, magnetite forms under more reducing conditions and is found in a wide variety of genetic types of deposits and rocks.
Its main deposits are of magmatic, contact-metasomatic and regionally metamorphic origin. Magnetite is also found in hydrothermal deposits.
1. In igneous rocks it is usually seen as disseminated. Magmatic deposits of titanomagnetite in the form of irregularly shaped accumulations and veins are often genetically associated with basic rocks (gabbro).
2. It is present in small quantities in many pegmatites in paragenesis with biotite, sphene, apatite and other minerals.
3. In contact-metasomatic formations, it often plays a very significant role, accompanied by garnets, pyroxenes, chlorites, sulfides, calcite and other minerals. There are known large deposits formed at the contact of limestones with granites and syenites.
4. As a companion magnetite is found in hydrothermal deposits, mainly in association with sulfides (pyrrhotite, pyrite, chalcopyrite, etc.). Relatively rarely, it forms independent deposits in association with sulfides, apatite, and other minerals. The largest deposits of this type in Russia are known in the Angara-Ilimsk region of Siberia.
5. In exogenous conditions the formation of magnetite can occur only in exceptional cases. The presence of magnetite grains in modern sea mud is believed to be the result of not only their removal from land in the form of debris, but also in the form of new formations in situ due to iron hydroxides under the reducing effect of decomposing organic matter.
6. During regional metamorphism, magnetite, like hematite, arises during the dehydration of iron hydroxides formed in sedimentary rocks during exogenous processes, but under reducing conditions (with a lack of oxygen). This type of formations includes many large-sized stratal deposits of hematite-magnetite ores found among metamorphosed sedimentary strata.
In the oxidation zone, it is a relatively stable mineral. When weathering, it is very difficult to hydrate, that is, to be converted into iron hydroxides. This process is rarely observed.
and relatively small in size.
Phenomenon martitization(the formation of pseudomorphs of hematite over magnetite) is observed in hot climate zones. Locally manifested martitization of magnetite is also established in hydrothermal and metamorphosed deposits without any connection with exogenous processes.
With the mechanical destruction of rocks, it frees itself from its satellites and everywhere passes into placers. Therefore, they concentrate in river and sea sands, sometimes creating a magnetite beach. Magnetite is the main part in black concentrates obtained by washing gold-bearing sands.
Photo of octahedral crystals in shale Practical use
Magnetite, like hematite, is the most important ore for iron. Titanomagnetites serve as ore for vanadium.
Magnetite ores, often containing about 60% iron, are the most important raw materials for smelting iron and steel. Phosphorus is considered harmful impurities in the ore, the content of which in the Bessemer smelting method should not exceed 0.05%, and for high-quality metal - 0.03%, and sulfur, the maximum maximum content of which should not exceed 1.5%. When melting ores according to the Thomas method, in which phosphorus is transferred into slag, its content should be not less than 0.61 and not more than 1.50%. The resulting phosphorous slag is called tomoslag and is used as fertilizer.
When smelting titanomagnetite ores, vanadium is extracted from slags, which is of great importance in the manufacture of high-quality steels. Vanadium pentoxide is also used in the chemical industry, and as a dye in ceramics and for other purposes.
How magnetite is mined Deposits
Of the numerous deposits in Russia, we will give only a few examples.
Among magmatic deposits refers Kusinskoe birthplace titanomagnetite, which also contains an increased amount of vanadium (in the Urals, 18 km north of Zlatoust). This deposit is represented by solid ore veins occurring among the parent altered igneous rocks of the gabbro formation. Here magnetite is closely associated with ilmenite and chlorite.
The Kopanskoe deposit of Ti-magnetite is being developed in the southern Urals.
An example contact metasomatic deposits is the famous Mount Magnetic(Southern Urals).
Powerful magnetite deposits are located among garnet, pyroxene-garnet and garnet epidote skarns, formed under the influence of granite magma on limestones. In some areas of ore deposits, magnetite is associated with primary hematite. The ores below the oxidation zone contain disseminated sulfides (pyrite, occasionally chalcopyrite,