Xifengite | |
---|---|
General | |
Category | Native element minerals |
Formula (repeating unit) | Fe5Si3 |
IMA symbol | Xif [1] |
Strunz classification | 1.BB.40 |
Crystal system | Hexagonal |
Crystal class | Dihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m) |
Space group | P63/mcm |
Unit cell | a = 6.759(5) c = 4.720(5) [Å]; Z = 2 |
Identification | |
Color | Gray, steel-black |
Crystal habit | As inclusions |
Mohs scale hardness | 5 |
Luster | Metallic |
Streak | Black |
Diaphaneity | Opaque |
References | [2] [3] |
Xifengite (Fe 5 Si 3) is a rare metallic iron silicide mineral. The crystal system of xifengite is hexagonal. It has a specific gravity of 6.45 and a Mohs hardness of 5.5. It occurs as steel gray inclusions within other meteorite derived nickel iron mineral phases.
It was first described in 1984 and named for the eastern passageway, Xifengkou, of the Great Wall of China. The type locality is the Yanshan meteorite of the Hebei Province, China. It has also been reported from dredgings along the East Pacific Rise.
The other known natural iron silicide minerals are gupeiite (Fe3Si), hapkeite (Fe2Si), linzhiite (FeSi2), luobusaite (Fe0.84Si2), naquite (FeSi), suessite ((Fe,Ni)3Si), and zangboite (TiFeSi2). [4]
Hibonite is a mineral with the chemical formula (Ca,Ce)(Al,Ti,Mg)12O19, occurring in various colours, with a hardness of 7.5–8.0 and a hexagonal crystal structure. It is rare, but is found in high-grade metamorphic rocks on Madagascar. Some presolar grains in primitive meteorites consist of hibonite. Hibonite also is a common mineral in the Ca-Al-rich inclusions found in some chondritic meteorites. Hibonite is closely related to hibonite-Fe ) an alteration mineral from the Allende meteorite. Hibonites were among the first minerals to form as the disk of gas and dust swirling around the young sun cooled.
Hapkeite is a mineral discovered in the Dhofar 280 meteorite found in 2000 in Oman on the Arabian Peninsula. The meteorite is believed to originate from the Moon; specifically, it appears to be a fragment of lunar highland breccia. Hapkeite's composition is of silicon and iron, and it is similar to other silicon-iron minerals found on Earth. An impact on the Moon is thought to have launched the partially molten or vaporized material into orbit.
Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of FeCr2O4. It is an oxide mineral belonging to the spinel group. The element magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (MgCr2O4). A substitution of the element aluminium can also occur, leading to hercynite (FeAl2O4). Chromite today is mined particularly to make stainless steel through the production of ferrochrome (FeCr), which is an iron-chromium alloy.
Cohenite is a naturally occurring iron carbide mineral with the chemical structure (Fe, Ni, Co)3C. This forms a hard, shiny, silver mineral which was named by E. Weinschenk in 1889 after the German mineralogist Emil Cohen, who first described and analysed material from the Magura meteorite found near Slanica, Žilina Region, Slovakia. Cohenite is found in rod-like crystals in iron meteorites.
Oldhamite is a calcium magnesium sulfide mineral with the chemical formula (Ca,Mg)S. Ferrous iron may also be present in the mineral resulting in the chemical formula (Ca,Mg,Fe)S. It is a pale to dark brown accessory mineral in meteorites. It crystallizes in the cubic crystal system, but typically occurs as anhedral grains between other minerals.
Troilite is a rare iron sulfide mineral with the simple formula of FeS. It is the iron-rich endmember of the pyrrhotite group. Pyrrhotite has the formula Fe(1-x)S which is iron deficient. As troilite lacks the iron deficiency which gives pyrrhotite its characteristic magnetism, troilite is non-magnetic.
Babingtonite is a calcium iron manganese inosilicate mineral with the formula Ca2(Fe,Mn)FeSi5O14(OH). It is unusual in that iron(III) completely replaces the aluminium so typical of silicate minerals. It is a very dark green to black translucent mineral crystallizing in the triclinic system with typically radial short prismatic clusters and druzy coatings. It occurs with zeolite minerals in cavities in volcanic rocks. Babingtonite contains both iron(II) and iron(III) and shows weak magnetism. It has a Mohs hardness of 5.5 to 6 and a specific gravity of 3.3.
Pigeonite is a mineral in the clinopyroxene subgroup of the pyroxene group. It has a general formula of (Ca,Mg,Fe)(Mg,Fe)Si2O6. The calcium cation fraction can vary from 5% to 25%, with iron and magnesium making up the rest of the cations.
Haxonite is an iron nickel carbide mineral found in iron meteorites and carbonaceous chondrites. It has a chemical formula of (Fe,Ni)23C6, crystallises in the cubic crystal system and has a Mohs hardness of 5+1⁄2 - 6.
Brownleeite is a silicide mineral with chemical formula MnSi. It was discovered by researchers of the Johnson Space Center in Houston while analyzing the Pi Puppid particle shower of the comet 26P/Grigg-Skjellerup. The only other known natural manganese silicide is mavlyanovite, Mn5Si3.
Roaldite is a rare meteorite mineral containing iron, nickel and nitrogen. Its chemical formula is (Fe,Ni)4N.
Suessite is a rare iron silicide mineral with chemical formula: Fe3Si. The mineral was named after Professor Hans E. Suess. It was discovered in 1982 during the chemical analysis of The North Haig olivine pigeonite achondrite (ureilite). It is a cream white color in reflected light, and ranges in size from 1 μm "blebs" to elongated grains that can reach up to 0.45 cm in length. This mineral belongs in the isometric crystal class. The isometric class has crystallographic axes that are all the same length and each of the three axes perpendicular to the other two. It is isotropic, has a structural type of DO3 and a crystal lattice of BiF3.
Carlsbergite is a nitride mineral that has the chemical formula CrN, or chromium nitride.
Djerfisherite is an alkali copper–iron sulfide mineral and a member of the djerfisherite group.
Hexamolybdenum is a molybdenum dominant alloy discovered during a nanomineralogy investigation of the Allende meteorite. Hexamolybdenum was discovered in a small ultrarefractory inclusion within the Allende meteorite. This inclusion has been named ACM-1. Hexamolybdenum is hexagonal, with a calculated density of 11.90 g/cm3. The new mineral was found along with allendeite. These minerals, are believed to demonstrate conditions during the early stages of the Solar System, as is the case with many CV3 carbonaceous chondrites such as the Allende meteorite. Hexamolybdenum lies on a continuum of high-temperature alloys that are found in meteorites and allows a link between osmium, ruthenium, and iron rich meteoritic alloys. The name hexamolybdenum refers to the crystal symmetry and the molybdenum rich composition. The Allende meteorite fell in 1969 near Pueblito de Allende, Chihuahua, Mexico.
Linzhiite is an iron silicide mineral with the formula FeSi2. It was discovered in the 1960s in Donetsk Oblast in Soviet Union, and named ferdisilicite, but was not approved by the International Mineralogical Association. It was later rediscovered near Linzhi in Tibet. Linzhiite occurs together with other rare iron silicide minerals, xifengite (Fe5Si3) and naquite (FeSi).
Naquite is a mineral of iron monosilicide, FeSi. It was discovered in the 1960s in Donetsk Oblast in Soviet Union, and named fersilicite, but was not approved by the International Mineralogical Association. It was later rediscovered in the Nagqu area of Tibet and given the name naquite. Naquite occurs together with other rare iron silicide minerals, xifengite (Fe5Si3) and linzhiite (FeSi2).
Iron disilicide (FeSi2) is an intermetallic compound, a silicide of iron that occurs in nature as the rare mineral linzhiite. At room temperature it forms orthorhombic crystals (β phase), which convert into a tetragonal α phase upon heating to 970 °C.
Phosphide silicides or silicide phosphides or silicophosphides are compounds containing anions composed of silicide (Si4−) and phosphide (P3−). They can be considered as mixed anion compounds. They are distinct from the phosphidosilicates, which have the phosphorus bonded to the silicon. Related compounds include the phosphide carbides, germanide phosphides, nitride silicides, and antimonide silicides.
Chukanovite is an iron(II) hydroxide-carbonate mineral with the ideal chemical formula Fe+22(CO3)(OH)2. It is a member of the rosasite mineral group and crystalizes in the monoclinic crystal system. Upon initial crystallization, it is typically pale green to colorless, but it takes on a brownish green hue after being altered at the surface. As a weathering product of meteoritic iron, chukanovite is a relatively uncommon mineral on Earth, having only been discovered in the year 2000. However, it is commonly formed artificially as a corrosion byproduct through the manufacturing of sand-deposited carbon steel.