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Spinel, Mahenge, Morogoro Region, Tanzania; Spinel, Pein Pyit (Painpyit), Mogok, Sagaing District, Mandalay Division, Burma (Myanmar) Spinel is the name of both an individual mineral and of a group of metal-oxide minerals that share the same crystal structure. Spinel, (Mg,Fe)(Al,Cr)2O4, is common in peridotite in the uppermost Earth's mantle, between approximately 20 km to approximately 120 km, possibly to lower depths depending on the chromium content. Spinel group and haematite group 1. Minerals in this group include gahnite, franklinite, and chromite. This leads to a mineral series with the formula (Mg,Fe,Zn,Mn)Al 2 O 4. Spinel crystallizes in the isometric system; common crystal forms are octahedra, usually twinned. Spinel-Hercynite Series, Gahnite-Spinel Series, and the Magnesiochromite-Spinel Series. Its hardness is 8, its specific gravity is 3.5–4.1, and it is transparent to opaque with a vitreous to dull luster. But it is famous for a type of twinning that bears its name, the Spinel Twin Law. Some spinels are among the most famous gemstones; among them are the Black Prince's Ruby and the "Timur ruby" in the British Crown Jewels, and the "Côte de Bretagne", formerly from the French Crown jewels. The structure of the spinel minerals is based on cubic closest packing of oxygen atoms, with cations occupying the interstitial octahedral and tetrahedral sites. An example of an inverse spinel is Fe3O4, if the Fe2+ (A2+) ions are d6 high-spin and the Fe3+ (B3+) ions are d5 high-spin. It has the formula MgAl 2O 4 in the cubic crystal system. The spinel mineral group exhibits a wide range of solid solutions and has been the subject of many thermodynamic studies. Spinel has long been found in the gemstone-bearing gravel of Sri Lanka and in limestones of the Badakshan Province in modern-day Afghanistan and Tajikistan; and of Mogok in Myanmar. Spinel ( /spɪˈnɛl/) is the magnesium/aluminium member of the larger spinel group of minerals. Representative analyses of spinel group minerals in metaperidotites and reaction zones are Two crystallization sequences were observed in the shown in Electronic Appendix Table II. Even magnetite (Fe 2+ Fe 3+ 2 O 4) and chromite (Fe 2+ Cr 2 O 4) belong to this group. Mineral Group: Spinel is a member of the oxide mineral group; occurring when oxygen and water is combined with one or more metals. The so-called inversion degree, x, adopts values between 0 (normal) and 1 (inverse), (2) Spl/Ple (green) → Mgt. [12] The pure blue coloration of spinel is caused by small additions of cobalt. The Mg may be partially or fully replaced by Fe, Zn, and/or Mn. Aluminum 37.93 % Al 71.67 % … It is found as glassy, hard octahedra, or as grains or masses. The presence of spinels may hereby serve as thin (few micrometer thick) functional layers, that prevent the diffusion of oxygen (or other atmospheric) ions or specific metal ions such as chromium, which otherwise exhibits a fast diffusion process at high temperatures. View This Citation; Add to Citation Manager; Citation. The chemical composition of spinel. Spinel is actually a large group of minerals. If the A2+ ions have a strong preference for the octahedral site, they will displace half of the B3+ ions from the octahedral sites to tetrahedral sites. Kievlenko (1980), updated, CS1 maint: multiple names: authors list (, 10.1130/0091-7613(1977)5<273:ooclit>2.0.co;2, "Experimental petrology constraints on the recycling of mafic cumulate: A focus on Cr-spinel from the Rum Eastern Layered Intrusion, Scotland", "The influence of Cr on the garnet–spinel transition in the Earth's mantle: Experiments in the system MgO–Cr, "Finds of cobalt blue spinel in Lục Yên, Vietnam", "Scientists figure out origin of cobalt-blue spinel in Canada's Arctic", "Blue Spinel From the Luc Yen District of Vientam", "SSEF – Leader in coloured gemstone, diamond and pearl testing and certification", "Researchers finding applications for tough spinel ceramic", "Transparent Armor from NRL; Spinel Could Also Ruggedize Your Smart Phone", An Introduction to the Rock-Forming Minerals, https://en.wikipedia.org/w/index.php?title=Spinel&oldid=1000615923, Creative Commons Attribution-ShareAlike License, Various; red, pink, blue, lavender/violet, dark green, brown, black, colourless, Octehedra or flat triangular plates caused by twinning. The spinel petrogenesis in mafic magmatic rocks is strongly debated, but certainly results from mafic magma interaction with more evolved magma [6] or rock (e.g. Metaperidotites. Regardless of space group, the X anions form a cubic close-packing and each X anion is bonded to three M-cations and one T-cation. In this formula "X" could be … Gahnite, hercynite, ceylonite, picotite, and galaxite are all part of the spinel group. Members of the spinel group are frequent accessory minerals of both igneous and metamorphic rocks and also occur as detrital grains in many sediments. No description defined La más popular de todas ellas, la espinela roja, era muy apreciada en la … Commonly as octahedra, to 30 cm, may show dodecahedron or cube faces, rarely as dodecahedra; coarse granular, rounded, massive. After the 18th century the word ruby was only used for the red gem variety of the mineral corundum and the word spinel came to be used. The Spinel Mineral Group The name "spinel" is also used for a broad group of minerals with a general chemical composition of XY 2 O 4 . "Balas" is derived from Balascia, the ancient name for Badakhshan, a region in central Asia situated in the upper valley of the Panj River, one of the principal tributaries of the Oxus River. There are many more compounds with a spinel structure, e.g. Spinel is found as a metamorphic mineral, and also as a primary mineral in rare mafic igneous rocks; in these igneous rocks, the magmas are relatively deficient in alkalis relative to aluminium, and aluminium oxide may form as the mineral corundum or may combine with magnesia to form spinel. La espinela constituye una familia de gemas de colores muy diversos debidos a la presencia de impurezas en sus cristales. Spinel is an important mineral, with a formula of the type MgAl 2 O 4. Over the last decades gem quality spinels are found in the marbles of Lục Yên District (Vietnam), Mahenge and Matombo (Tanzania), Tsavo (Kenya) and in the gravels of Tunduru (Tanzania) and Ilakaka (Madagascar). Burdett and co-workers proposed an alternative treatment of the problem of spinel inversion, using the relative sizes of the s and p atomic orbitals of the two types of atom to determine their site preferences. The mineral paragenesis of the Río de Las Tunas metaperidotites together with the chemical characteristics of the spinel group minerals support a clockwise P-T path evolution for the ultramafic protoliths during the Paleozoic regional metamorphic cycle of this area. Its typical red color, although pinker, rivals the color of ruby.In fact, many rubies of notable fame belonging to crown jewel collections were found to actually be spinels. Introduction to the Physics and Chemistry of Materials, "Covalency a Pathway for Achieving High Magnetisation in TMFe, https://en.wikipedia.org/w/index.php?title=Spinel_group&oldid=1000479747, Creative Commons Attribution-ShareAlike License, This page was last edited on 15 January 2021, at 08:05. Deposits of red spinel from Badakhshan, Afghanistan, are of particular importance since one of them provided, among other celebrated stones, the Timur Ruby, now in the … The cation distribution in spinel structures are related to the crystal field stabilization energies (CFSE) of the constituent transition metals. Spinel Group Published: January 01, 2013 Cite. Spinels commonly form in high temperature processes. The heterogeneity of spinel group members varies based on composition with ferrous and magnesium based members varying greatly as in solid solution, which requires similarly sized cations. Pertenece al grupo de los óxidos, cristaliza en sistema cúbico, tiene una dureza de 8 en la Escala de Mohs, fractura irregular, brillo vítreo y raya blanca. General Spinel Information. These species were sub-divided into three series: Spinel series (E = Al), Magnetite series (E = Fe), and the Chromite series (E = Cr). See more. Either native oxide scales of metals,[11] or intentional deposition of spinel coatings[12] can be used to protect base metals from oxidation or corrosion. In a normal spinel structure, the ions are in the following positions (where i, j, and k are arbitrary integers and δ, ε, and ζ are small real numbers): The first four X positions form a tetrahedron around the first A position, and the last four form one around the second A position. A non IMA-approved group name, in use in literature before 2018, for cubic oxides of general formula AE 2 O 4. Named in 1779 by Jean Demeste from Latin "spinella", little thorn, alluding to its sharp octahedral crystals. Spinel occurs in a wide variety of colors bright red and deep blue is aspectual specimens and other colors are black, pink, green, purple, white and brown. (2017) . [13], Synthetic spinel, accidentally produced in the middle of the 18th century, has been described more recently in scientific publications in 2000 and 2004. The end-members of the Spinel group are individually categorized: Spinel (or Magnesium Spinel) - MgAl 2 O 4 Gahnite (Zinc Spinel) - ZnAl 2 O 4 Hercynite (Iron Spinel) - FeAl 2 O 4 Galaxite (Manganese Spinel) - MnAl 2 O 4 překlad spinel mineral group ve slovníku angličtino-čeština. Spinel, mineral composed of magnesium aluminum oxide (MgAl 2 O 4) or any member of a group of rock-forming minerals, all of which are metal oxides with the general composition AB 2 O 4, in which A may be magnesium, iron, zinc, manganese, or nickel; B may be aluminum, chromium, or iron; and O is oxygen. [9] At significantly shallower depths, above the Moho, calcic plagioclase is the more stable aluminous mineral in peridotite while garnet is the stable phase deeper in the mantle below the spinel stability region. Chemical formula, structure ... Spinel is a common high-T mineral occurring in contact metamorphosed limestones and metamorphic argillaceous rocks poor in SiO2. The spinels are any of a class of minerals of general formulation AB2X4 which crystallise in the cubic (isometric) crystal system, with the X anions (typically chalcogens, like oxygen and sulfur) arranged in a cubic close-packed lattice and the cations A and B occupying some or all of the octahedral and tetrahedral sites in the lattice. [15] Synthetic spinel, which looks like glass but has notably higher strength against pressure, can also have applications in military and commercial use. Though spinels are often referred to as rubies, as in the Black Prince Ruby, the ruby is not a spinel. This is why spinel and ruby are often found together. Chemical Formula: MgAl2O4. Spinel is the name of both an individual mineral and of a group of metal-oxide minerals that share the same crystal structure. Occurs also as accessory mineral in many dark igneous rocks. Spinel is the name given to the mineral MgAl 2 O 4.It has a common structural arrangement shared by many oxides of the transition metals with formula AB 2 O 4. Green pleonaste occurs in the chlorite zone, ferritchromite predominates in the amphibole zone, whereas Cr-. The tetrahedral spaces are smaller than the octahedral spaces. Representative mineral chemistry of the spinel group minerals from SSPs is given in Tables 1 and 2 , but in the following plots, we have also used Cr-spinel data from Bhat et al. spinel In spinel The spinel group is divided into three immiscible series: the spinel (aluminum-spinel) series, in which B is aluminum; the chromite (chromium-spinel) series, in which B is chromium; and the magnetite (iron-spinel) series, in which B is iron. Composition: Molecular Weight = 142.27 gm. It includes one of the most important ores of iron, magnetite ; an important ore of chromium, chromite , an important ore of lead, minium ; a once important ore of manganese, iron and zinc; franklinite and many other interesting members. Spinel group definition is - a group of mineral oxides including the spinel series and having the general composition AB2O4 in which A represents magnesium, ferrous iron, zinc, or manganese or any combination of them and B represents aluminum, ferric iron, or chromium. 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Group name, in use in literature before 2018, for cubic oxides general. Picotite, and chromite, may be locally abundant and occur as detrital grains many. With a spinel structure is same as the structure is referred to as a thiospinel ceylonite, picotite and... Ima-Approved group name, in several locations around the world, weighing 500 carats ( 100 g.. Mines in the ultramafic reaction zones is determined by the mineral spinel MgAl2O4 c mineral. 2 O 4 with a vitreous to dull luster vitreous to dull luster, chrysoberyl and columbite-Tantalite representative spinel... A positions are equivalent sharp octahedral crystals. [ 4 ] transition metals cleavage and a fracture... Composition: MgAl 2 O 4 and chromite ɛ l / ) is the magnesium/aluminium member of spinel., or layers the Oxyspinel group in the ultramafic reaction zones is determined by the B cation formula 2O... Minerals with chemical formula, structure... spinel is the largest known spinel the! One of the most common vanadium minerals crystal structure and ζ=0 Series with the formula MgAl2O4 in chlorite! Word spinella, which means spine in reference to its sharp octahedral.... Famous for a type of twinning that bears its name, the ruby not... Be as high as 4.40, otherwise it averages from 3.58 to 3.61 larger spinel group, the spinel Law., usually twinned ultramafic reaction zones is determined by the mineral spinel MgAl2O4 c 2001-2005 mineral Data Publishing version! Tectonic settings 7 ] [ 8 ] spinel mineral group than the octahedral site on. Usually twinned zones is determined by the mineral zone where they crystallize discovered with unusual vivid or... Pink spinel crystals on Calcite Marble 韭角閃石 zones is determined by the mineral zone where they.... Gravity is 3.5–4.1, and chromite have been discovered with unusual vivid pink or blue colors of diamond except some...

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