Kamacite is an alloy of iron and nickel, which is found on Earth only in meteorites. According to the International Mineralogical Association (IMA) it is considered a proper nickel-rich variety of the mineral native iron. The proportion iron:nickel is between 90%:10% and 95%:5%; small quantities of other elements, such as cobalt or carbon may also be present. The mineral has a metallic luster, is gray and has no clear cleavage although its crystal structure is isometric-hexoctahedral. Its density is about 8 g/cm3 and its hardness is 4 on the Mohs scale. It is also sometimes called balkeneisen.
In meteoritics, a meteorite classification system attempts to group similar meteorites and allows scientists to communicate with a standardized terminology when discussing them. Meteorites are classified according to a variety of characteristics, especially mineralogical, petrological, chemical, and isotopic properties.
A chondrule is a round grain found in a chondrite. Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids. Because chondrites represent one of the oldest solid materials within the Solar System and are believed to be the building blocks of the planetary system, it follows that an understanding of the formation of chondrules is important to understand the initial development of the planetary system.
A chondrite is a stony (non-metallic) meteorite that has not been modified, by either melting or differentiation of the parent body. They are formed when various types of dust and small grains in the early Solar System accreted to form primitive asteroids. Some such bodies that are captured in the planet's gravity well become the most common type of meteorite by arriving on a trajectory toward the planet's surface. Estimates for their contribution to the total meteorite population vary between 85.7% and 86.2%.
Forsterite (Mg2SiO4; commonly abbreviated as Fo; also known as white olivine) is the magnesium-rich end-member of the olivine solid solution series. It is isomorphous with the iron-rich end-member, fayalite. Forsterite crystallizes in the orthorhombic system (space group Pbnm) with cell parameters a 4.75 Å (0.475 nm), b 10.20 Å (1.020 nm) and c 5.98 Å (0.598 nm).
Enstatite is a mineral; the magnesium endmember of the pyroxene silicate mineral series enstatite (MgSiO3) – ferrosilite (FeSiO3). The magnesium rich members of the solid solution series are common rock-forming minerals found in igneous and metamorphic rocks. The intermediate composition, (Mg,Fe)SiO
3, has historically been known as hypersthene, although this name has been formally abandoned and replaced by orthopyroxene. When determined petrographically or chemically the composition is given as relative proportions of enstatite (En) and ferrosilite (Fs) (e.g., En80Fs20).
Hedenbergite, CaFeSi2O6, is the iron rich end member of the pyroxene group having a monoclinic crystal system. The mineral is extremely rarely found as a pure substance, and usually has to be synthesized in a lab. It was named in 1819 after M.A. Ludwig Hedenberg, who was the first to define hedenbergite as a mineral. Contact metamorphic rocks high in iron are the primary geologic setting for hedenbergite. This mineral is unique because it can be found in chondrites and skarns (calc–silicate metamorphic rocks). Since it is a member of the pyroxene family, there is a great deal of interest in its importance to general geologic processes.
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.
Xifengite (Fe5Si3) 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.
Keilite is an iron-magnesium sulfide mineral with the chemical formula (Fe,Mg)S) that is found in enstatite chondrites. Keilite is the iron-dominant analog of niningerite. Keilite is named after Klaus Keil.
Niningerite is a magnesium-iron-manganese sulfide mineral with the chemical formula MgS that is found in enstatite chondrite meteorites. Niningerite is the magnesium-dominant analog of keilite. This mineral is named after Harvey H. Nininger.
Cubanite is a copper iron sulfide mineral that commonly occurs as a minor alteration mineral in magmatic sulfide deposits. It has the chemical formula CuFe2S3 and when found, it has a bronze to brass-yellow appearance. On the Mohs hardness scale, cubanite falls between 3.5 and 4 and has a orthorhombic crystal system. Cubanite is chemically similar to chalcopyrite, however it is the less common copper iron sulfide mineral due to crystallization requirements.
Enstatite chondrites are a rare form of meteorite, rich in the mineral enstatite. Only about 200 E-Type chondrites are currently known, comprising about 2% of the chondrites that fall on Earth. There are two main subtypes: EH and EL, classified based on their iron content.
Wassonite is an extremely rare titanium sulfide mineral with chemical formula TiS. Its discovery was announced in a 2011 NASA press release as a single small grain within an enstatite chondrite meteorite called "Yamato 691", which was found during a 1969 Japanese expedition to Antarctica. This grain represents the first observation in nature of the synthetic compound titanium(II) sulfide.
Sinoite is rare mineral with the chemical formula Si2N2O. It was first found in 1905 in chondrite meteorites and identified as a distinct mineral in 1965. Sinoite crystallizes upon meteorite impact as grains smaller than 0.2 mm surrounded by Fe-Ni alloys and the mineral enstatite. It is named after its SiNO composition and can be prepared in the laboratory as a silicon oxynitride ceramic.
Lodranites are a small group of primitive achondrite meteorites that consists of meteoric iron and silicate minerals. Olivine and pyroxene make up most of the silicate minerals. Like all primitive achondrites lodranites share similarities with chondrites and achondrites.
The Zakłodzie meteorite is a stony-iron meteorite found in Poland in 1998. Its mass is 8.68 kilograms (19.1 lb). It is composed predominantly from enstatite and meteoric iron. Currently classified as an ungrouped enstatite achondrite its classification is still an ongoing scientific debate.
The Itqiy meteorite is an enstatite-rich stony-iron meteorite. It is classified as an enstatite chondrite of the EH group that was nearly melted and is therefore very unusual for that group. Other classifications have been proposed and are an ongoing scientific debate.
Tetrataenite is a native metal alloy composed of chemically-ordered L10-type FeNi, recognized as a mineral in 1980. The mineral is named after its tetragonal crystal structure and its relation to the iron-nickel alloy, taenite. It is one of the mineral phases found in meteoric iron.
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.
