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Stony–iron Meteorite
Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of meteoric iron and silicates. This distinguishes them from the stony meteorites, that are mostly silicates, and the iron meteorites, that are mostly meteoric iron. Stony-iron meteorites are all differentiated, meaning that they show signs of alteration. They are therefore achondrites. The stony-irons are divided into mesosiderites and pallasites. Pallasites have a matrix of meteoric iron with embedded silicates (most of it olivine). Mesosiderites are breccias which show signs of metamorphism. The meteoric iron occurs in clasts instead of a matrix.Karl K. Turekian. ''Meteorites, comets, and planets'112/ref> They are in the top rank of all Meteorite classification schemes, usually called "Type". Mineralogy The meteoric iron of stony-irons is similar to that of iron meteorites, consisting mostly of kamacite and taenite in different proportions. The silicates are dominated by olivine. Accessory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kamacite
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. The name was coined in 1861 and is derived from the Greek root ''καμακ-'' "kamak" or ''κάμαξ'' "kamaks", meaning vine-pole. It is a major constituent of iron meteorites (octahedrite and hexahedrite types). In the octahedrites it is found in bands interleaving with taenite forming Widmanstätten patterns. In hexahedrites, fine parallel lines called Neumann lines are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carlsbergite
Carlsbergite is a nitride mineral that has the chemical formula CrN, or chromium nitride. It is named after the Carlsberg Foundation which backed the recovery of the Agpalilik fragment of the Cape York meteorite in which the mineral was first described. It occurs in meteorites along the grain boundaries of kamacite (nickel-rich native iron) or troilite (FeS: iron sulfide) in the form of tiny plates. It occurs associated with kamacite, taenite, daubreelite, troilite and sphalerite, . In addition to the Cape York meteorite, carlsbergite has been reported from: * the North Chile meteorite in the Antofagasta Province, Chile * the Nentmannsdorf meteorite of Bahretal, Erzgebirge, Saxony * the Okinawa Trough, Senkaku Islands, Okinawa Prefecture, Japan * the Uwet meteorite of Cross River State, Nigeria * the Sikhote-Alin meteorite, Sikhote-Alin Mountains, Russia * the Hex River Mountains meteorite from the Cape Winelands District, Western Cape Province, South Africa * the Canyon D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troilite
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 (x = 0 to 0.2) which is iron deficient. As troilite lacks the iron deficiency which gives pyrrhotite its characteristic magnetism, troilite is non-magnetic. Troilite can be found as a native mineral on Earth but is more abundant in meteorites, in particular, those originating from the Moon and Mars. It is among the minerals found in samples of the meteorite that struck Russia in Chelyabinsk on February 15th, 2013. Uniform presence of troilite on the Moon and possibly on Mars has been confirmed by the Apollo, Viking program, Viking and Phobos program, Phobos space probes. The relative intensities of isotopes of sulfur are rather constant in meteorites as compared to the Earth minerals, and therefore troilite from Canyon Diablo (meteorite), Canyon Diablo meteorite is chosen as the Reference materials for stable isotope a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tridymite
Tridymite is a high-temperature polymorph of silica and usually occurs as minute tabular white or colorless pseudo-hexagonal crystals, or scales, in cavities in felsic volcanic rocks. Its chemical formula is Si O2. Tridymite was first described in 1868 and the type location is in Hidalgo, Mexico. The name is from the Greek ''tridymos'' for ''triplet'' as tridymite commonly occurs as twinned crystal '' trillings'' (compound crystals comprising three twinned crystal components). Structure Tridymite can occur in seven crystalline forms. Two of the most common at standard pressure are known as α and β. The α-tridymite phase is favored at elevated temperatures (>870 °C) and it converts to β-cristobalite at 1470 °C. However, tridymite does usually not form from pure β-quartz, one needs to add trace amounts of certain compounds to achieve this. Otherwise the β-quartz-tridymite transition is skipped and β-quartz transitions directly to cristobalite at 1050 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schreibersite
Schreibersite is generally a rare iron nickel phosphide mineral, , though common in iron-nickel meteorites. It has been found on Disko Island in Greenland and Illinois. Another name used for the mineral is rhabdite. It forms tetragonal crystals with perfect 001 cleavage. Its color ranges from bronze to brass yellow to silver white. It has a density of 7.5 and a hardness of 6.5 – 7. It is opaque with a metallic luster and a dark gray streak. It was named after the Austrian scientist Carl Franz Anton Ritter von Schreibers (1775–1852), who was one of the first to describe it from iron meteorites.Schreibersite Webmineral Schreibersite is reported from the Magura Meteorite, Arva-(present name – Orava), Slovak Republic; the |
Pyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) or magnesium (Mg) and more rarely zinc, manganese or lithium, and Y represents ions of smaller size, such as chromium (Cr), aluminium (Al), magnesium (Mg), cobalt (Co), manganese (Mn), scandium (Sc), titanium (Ti), vanadium (V) or even iron (Fe II) or (Fe III). Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that crystallize in the orthorhombic system are known as orthopyroxenes. The name ''pyroxene'' is derived from the Ancient Greek words for 'f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merrillite
Merrillite is a calcium phosphate mineral with the chemical formula Ca9NaMg(PO4)7. It is an anhydrous, sodium-rich member of the merrillite ''group'' of minerals. Mineral species, sub-group and group Merrillite is a distinct '' mineral species'' but it also gives its name to a set of similar minerals, which together form the merrillite ''sub-group'' of minerals. The merrillite sub-group and the whitlockite sub-group together form the merrillite ''group'' of minerals. *Merrillite Group **Merrillite Sub-group *** Ferromerrillite *** Keplerite *** Matyhite ***Merrillite **Whitlockite Sub-group *** Hedegaardite *** Strontiowhitlockite ***Whitlockite *** Wopmayite In September 2022 the discovery of another merrillite group mineral, changesite–(Y), was announced, but, , it is not yet clear where this new mineral sits in the merrillite group hierarchy. Discovery and naming Merrillite is named after George P. Merrill (1854–1929) of the Smithsonian Institution. In 1915, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ilmenite
Ilmenite is a titanium-iron oxide mineral with the idealized formula . It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printing inks, fabrics, plastics, paper, sunscreen, food and cosmetics. Structure and properties Ilmenite is a heavy (specific gravity 4.7), moderately hard (Mohs hardness 5.6 to 6), opaque black mineral with a submetallic luster. It is almost always massive, with thick tabular crystals being quite rare. It shows no discernible cleavage, breaking instead with a conchoidal to uneven fracture. Ilmenite crystallizes in the trigonal system with space group ''R''. The ilmenite crystal structure consists of an ordered derivative of the corundum structure; in corundum all cations are identical but in ilmenite Fe2+ and Ti4+ ions occupy alternating layers perpendicular to the trigonal c axis. Pure ilmenite is paramagnetic (showing only very weak attra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphite
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large scale (300 kton/year, in 1989) for uses in pencils, lubricants, and electrodes. Under high pressures and temperatures it converts to diamond. It is a weak conductor of heat and electricity. Types and varieties Natural graphite The principal types of natural graphite, each occurring in different types of ore deposits, are * Crystalline small flakes of graphite (or flake graphite) occurs as isolated, flat, plate-like particles with hexagonal edges if unbroken. When broken the edges can be irregular or angular; * Amorphous graphite: very fine flake graphite is sometimes called amorphous; * Lump graphite (or vein graphite) occurs in fissure veins or fractures and appears as massive platy intergrowths of fibrous or acicular cryst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldspars and the ''alkali'' (potassium-sodium) feldspars. Feldspars make up about 60% of the Earth's crust, and 41% of the Earth's continental crust by weight. Feldspars crystalize from magma as both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. Compositions The feldspar group of minerals consists of tectosilicates, silicate minerals in which silicon ions are linked by shared oxygen ions to form a three-dimensional network. Compositions of major elements in common feldspars can be expressed in terms of three endmembers: * potassium feldspar (K- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daubréelite
Daubréelite is a rare sulfide mineral. It crystallizes with cubic symmetry and has chemical composition of Fe2+Cr3+2S4. It usually occurs as black platy aggregates. Naming and history Daubréelite was named after the French mineralogist, petrologist and meteoriticist Gabriel Auguste Daubrée. The mineral was first described in 1876 in the ''American Journal of Science''. Its type locality is the Coahuila meteorite, Bolsom de Mapimí, Coahuila, Mexico. Classification In the Nickel-Strunz classification daubréelite is part of the "Sulfides and Sulfosalts" and further a "metal sulfide with a metal-sulfide ratio of 3:4 and 2:3". Occurrences Daubréelite is found in iron meteorites as an inclusion in meteoric iron (kamacite and taenite). Further paragenetic minerals are alabandine, enstatite, graphite, plagioclase and schreibersite. According to one source daubréelite has been described from 34 localities. Some notable examples being the ALH 84001 meteorite, Hoba meteorite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cohenite
Cohenite is a naturally occurring iron carbide mineral with the chemical structure ( Fe, Ni, Co)3 C. 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.Vagn F. Buchwald, ''Handbook of Iron Meteorites,'' University of California Press, 1975 On Earth cohenite is stable only in rocks which formed in a strongly reducing environment and contain native iron deposits. Such conditions existed in some places where molten magmas invaded coal deposits, e.g. on Disko Island in Greenland, or at the Bühl near Kassel in Germany. Associated minerals include native iron, schreibersite, troilite and wustite. Similar iron carbides occur also in technical iron alloys and are called cementite. See also * Glossary of meteoritics *List of minerals *Li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
