Magnetite is a mineral from the group of oxides (iron oxide), with the chemical formula Fe3O4, where 72.4% of the volume is Fe, 27.6% O2, has its genesis in igneous rocks, metamorphic rocks and in deposits of hydrothermal replacement, its use is widespread as iron ore.
Properties and characteristics of magnetite
| Magnetite | Physical properties and characteristics |
|---|---|
| class, group | Rust (iron oxide) |
| Brightness | Metal. |
| Color | Iron black, black to silvery grey. |
| Stripe | Black. |
| Chemical formula | Fe3O4. |
| Chemical composition | Fe=72.4%, O=27.6% |
| Hardness | 6 |
| Specific weight or density | 5.18 g/cm3. |
| Cleavage or exfoliation | None. |
| Fracture | Subcoqueal to uneven. |
| Tenacity | Fragile. |
| crystalline system | Cubic. |
| Way of introducing yourself (habit) | Octahedral crystals, rarely dodecahedrons, massive, granular, fine grained. |
| Origin or geological environment | In igneous rocks, in contact and regional metamorphic rocks, and in hydrothermal replacement deposits. |
| associated rocks | Igneous (peridotites, gabbros and diorites), sedimentary (taconite) and metamorphic. |
| Associated minerals | Calcite, actinolite, biotite, hematite, pyrite, talc, epidote, hornblende, apatite, chlorite, almandine, phlogopite. |
| Applications | Iron ore, for collectors, indicator mineral of hydrothermal alterations and temperature. |
The magnetite It is a Fe3O4, its composition corresponds to the indicated formula, but in some cases low percentages of divalent magnesium and manganese have been found.
In crystallography it presents a cubic crystalline system. Its crystals have an octahedral habit, and usually present twins. They are also found in dodecahedrons and may be striated parallel to the edge with the octahedron. Although they are also found in solid granular or fine grained.
This mineral has an octahedral partition, the color is iron black with a metallic luster, it has a strong attraction for the common magnet, which is known as “lodestone” and it is opaque.
It has a hardness of 6 on the Mohs scale and a specific gravity of 5.18 g/cm3.
Magnetite stone meaning
In various cultures worldwide, various beliefs have been attributed to magnetite that have no scientific verification and are named below:
Within the esoteric field, magnetite is considered a special stone that emits extremely positive electromagnetic energies. Therefore it is believed that its vibrations eliminate fatigue, promote meditation, strengthen the intellect and is excellent for energizing amulets and talismans.
Since ancient times it has been given various magical properties capable of attracting love, giving good luck, driving away negative energies and protecting the spirit.
Esoteric properties and benefits
- The magnetite stone emits waves of magnetic energy capable of balancing and strengthening our entire bioenergetic field, also known as Aura.
- Its positive vibrations eliminate physical and mental fatigue, strengthen our self-healing power, help awaken psychic gifts and greatly favor telepathy.
- If used in meditation, it energizes the pineal gland, strengthens our intuition.
- It is also an excellent stone for energetic and spiritual protection, as it blocks energy vampirism attacks and dissolves all negative energies around you.
Origin, formation and geological environment.
This mineral is found in igneous, sedimentary, and metamorphic rocks. It is a common iron ore.
It is found disaggregated as an accessory mineral in various igneous rocks. In some types of magmatic segregation it is a main constituent of rocks and can form large masses of ore, these masses are generally titaniferous.
It is associated with crystalline metamorphic rocks and rocks rich in ferromagnesian minerals, such as peridotites, gabbros, and diorites. They are also found in huge layers and lentils in ancient metamorphic rocks.
This mineral is also found on the sea beaches, in the black sands. In fine sheets and debris between the mica sheets. Forming emery that is usually associated with corundum.
Hydrothermal alteration magnetite
This mineral is associated with various hydrothermal mineralization settings. Occurs in vein spreads and fills within early quartz-amphibole alteration in some porphyry deposits.
It is a common component in biotite-rich potassic alteration porphyry deposits and high concentrations are found in gold-rich porphyry deposits.
It is associated with various mineral deposit environments, including porphyry base metal, volcanic massive sulfide, skarn, and iron formations. This mineral is a significant component of tin and iron skarn deposits, as well as tungsten, copper, gold, and zinc-lead deposits.
It occurs in massive replacement bodies adjacent to intrusive sediment contact, as disseminated grains within late sedimentary breccias and thin distal bed replacement horizons.
Magnetite as “lodestone”
Referred to as the well-known “lodestone,” this form of magnetite attracts small amounts of iron, magnetites, and other magnetic objects.
The “lodestone” was the first indication that allowed humans to know the property of magnetism.
The first compasses were made with this material, these were suspended on a rope, when freely suspended on a rope, a small piece of lodestone will align with the magnetic field of the planet. They came into use in China in 300 BC. c.
Optical properties of magnetite
Parallel Nicols:
- Colour: Brownish gray
- Reflectivity: medium
- Bi-Reflectivity: none
- Pleochroism: none.
Crossed Nicols
- Anisotropy: Isotropic
- Internal reflections: none
Properties
- Shape: Anhedral.
It usually presents an octahedral crystal outline. In reflected light, it is gray, has no internal reflections, and is isotropic.
How to identify magnetite?
This mineral is characterized by the attraction to the common magnet, since few minerals have this characteristic, it is also the most strongly magnetic mineral that can be found in nature.
It is a black mineral and in some cases a blue iridescence is noted, with a metallic luster. It is exhibited as an octahedron, dodecahedron, or in granular masses. Its Mohs hardness is 6 and it differs from magnetic flanklinite by the line.
Uses of the mineral magnetite
- Important iron ore.
- As a toner in electrophotography
- Micronutrient in fertilizers
- pigments in paints
- Aggregate in high density concrete
- As a heavy medium, powdered magnetite can be mixed with a liquid to form a high-density slurry, which is used to separate specific gravities.
- As an abrasive, it is known as “emery”, it is naturally mixed corundum and magnetite. Synthetic emery is formed by mixing aluminum oxide with magnetite.
Benefits of magnetite in the earth’s magnetic field
Small crystals of this mineral are found in some rocks. In igneous rocks, when it crystallizes, small crystals of magnetites are formed in the melt and due to magnetism, they are oriented with the direction and polarity of the Earth’s magnetic field. As a result, the orientation of the Earth’s magnetic field at the time of rock crystallization is preserved.
Geologists can reconstruct the change in Earth’s magnetic field through the magnetic properties of rocks of various ages. How to learn about the movement of the continents over time.