Infobox mineral name Pyrope category Nesosilicate boxwidth 300 boxbgcolor image pyrope.jpg imagesize 250px caption A Gemstone gem quality, emerald cut pyrope. strunz 09.AD.25 formula Mg sub 3 sub Al sub ... Cr rich Pyrope Garnets ref habit Euhedral Euhedra typically display Rhombic dodecahedron rhombic ... This article is about the mineral. For the bird sometimes placed in the monotypic genus Pyrope, see Fire eyed Diucon . The mineral pyrope is a member of the garnet group. Pyrope is the only member of the garnet ... pyrope , and Bohemian garnet are two alternative names, the usage of the later being discouraged ... ruby . The composition of pure pyrope is Mg sub 3 sub Al sub 2 sub SiO sub 4 sub sub 3 sub , although ... Calcium Ca , Chromium Cr , Iron Fe and Manganese Mn . Pyrope forms a solid solution series with almandine ... in the pyrope structure. The resultant, mixed composition garnets are defined according to their pyrope almandine ratio. The semi precious stone rhodolite is a garnet of 70 pyrope composition. The origin of most pyrope is in ultramafic rocks, typically peridotite from the Earth s mantle these mantle .... Pyrope also occurs in u ltra h igh p ressure UHP metamorphic rocks, as in the Dora Maira massif in the western Alps. In that massif, nearly pure pyrope occurs in crystals to almost 12 cm in diameter some of that pyrope has inclusions of coesite , and some has inclusions of enstatite and sapphirine . Pyrope is common in peridotite xenoliths from kimberlite pipes, some of which are diamond bearing. Pyrope found in association with diamond commonly has a Cr sub 2 sub O sub 3 sub content of 3 8 , which ... pointing the origin of the pipe difficult. These varieties are known as chrome pyrope , or G9 G10 garnets. Mineral identification Image Garnet Group Pyrope Iron aluminum silicate Barton Mines, Gore Mountain, Warren County, New York 2861.jpg thumb left 180px Pyrope aggregate. In hand specimen, pyrope ... composition pyrope. Others, such as pyrope s high specific gravity, may be of little use when studying ... more details
Taxobox name Fire eyed Diucon image Fire eyed Diucon chp.JPG status LC status system IUCN3.1 regnum Animal ia phylum Chordate Chordata classis Aves ordo Passeriformes familia Tyrant flycatcher Tyrannidae genus Xolmis species X. pyrope binomial Xolmis pyrope binomial authority Heinrich von Kittlitz Kittlitz , 1830 synonyms Pyrope pyrope The Fire eyed Diucon Xolmis pyrope is a passerine bird of South America belonging to the tyrant flycatcher family Tyrannidae. It is usually placed with the monjitas in the genus Xolmis but was sometimes placed in its own genus Pyrope in the past. It is 19 21 cm long. The upperparts are mainly plain grey. The underparts are pale grey with white throat and undertail coverts. The eyes are bright coral red, for which the bird is named. It is found in central and southern Chile , southwestern Argentina , and Tierra del Fuego . Vagrant birds have occurred just eastwards of Tierra del Fuego in the Falkland Islands . References WilsonBull116 347. Jaramillo, Alvaro Burke, Peter & Beadle, David 2003 Field Guide to the Birds of Chile , Christopher Helm, London. Woods, Robin W. 1988 Guide to Birds of the Falkland Islands , Anthony Nelson, Oswestry. External links http ibc.hbw.com ibc phtml especie.phtml?idEspecie 5031 Fire eyed Diucon videos on the Internet Bird Collection commonscat Xolmis pyrope Tyrannidae stub Category Tyrannidae Category Xolmis Category Birds of Patagonia Category Birds of Chile Diucon, Fire eyed Category Birds of Argentina Diucon, Fire eyed Category Birds of Tierra del Fuego Diucon, Fire eyed es Xolmis pyrope fr P poaza il de feu sv Eld gd monjita ... more details
Infobox mineral name Rhodolite category Pyrope variety boxwidth boxbgcolor image Rhodolite in Matrix Garnet Group Magnesium iron aluminum silicate Macon County North Carolina 2904.jpg imagesize 200px caption formula Mg,Fe sub 3 sub Al sub 2 sub SiO sub 4 sub sub 3 sub molweight color light to dark purplish red through reddish purple habit system cubic twinning cleavage none, may show indistinct parting fracture conchoidal mohs 7 7.5 luster greasy to vitreous polish vitreous refractive 1.760 .010, .020 opticalprop Single refractive, often anomalous double refractive birefringence none dispersion .026 pleochroism none fluorescence inert absorption usually at 504, 520, and 573nm, may also have faint lines at 423, 460, 610 and 680 690nm streak gravity 3.84 .10 density melt fusibility diagnostic solubility diaphaneity other references ref Gia , Gemological. Gem Reference Guide. City Gemological Institute of America GIA , 1988. ISBN 0 87311 019 6 ref Rhodolite is a varietal name for rose pink to red mineral pyrope , a species in the garnet group. It is found in Cowee Valley , Macon County, North Carolina Macon County , North Carolina . ref http www.mindat.org min 6719.html mindat.org Rhodolite ref The name is derived from the Greek for rose like , in common with many pink mineral types e.g. rhodochrosite , rhodonite , but rhodolite itself is not officially recognised as a mineralogical term. This colouration, and the commonly Inclusion mineral inclusion free nature of garnet from this locality, has led to rhodolite being used as a semi precious gemstone . Chemically, rhodolite is an iron magnesium aluminium silicate, part of the pyrope almandine solid solution solid solution series, with an approximate garnet composition of Py sub 70 sub Al sub 30 sub . References references Silicate mineral stub Category Gemstones Category Garnet group fr Rhodolite ru sv Rodolit ... more details
Orphan date February 2009 Infobox mineral name Malaia garnet category Varietal name boxwidth boxbgcolor image imagesize caption formula Mg,Mn sub 3 sub Al sub 2 sub SiO sub 4 sub sub 3 sub ref name GRG Gia , Gemological. Gem Reference Guide. City Gemological Institute of America GIA , 1988. ISBN 0 87311 019 6 ref molweight color light to dark slightly pinkish orange, reddish orange, yellowish orange habit system cubic ref name GRG twinning cleavage none, may show indistinct parting ref name GRG fracture conchoidal ref name GRG mohs 7 7.5 ref name GRG luster vitreous ref name GRG polish vitreous to subadamantine ref name GRG refractive 1.760 .020, .018 ref name GRG opticalprop Single refractive, often anomalous double refractive ref name GRG birefringence none ref name GRG dispersion pleochroism none ref name GRG fluorescence inert ref name GRG absorption strong lines at 410, 420, 430nm, that may merge to form cutoff below 435nm. Also some combination of lines at 460, 480, 504, 520, or 573nm. ref name GRG streak gravity 3.78 3.85 ref name GRG density melt fusibility diagnostic solubility diaphaneity other Malaia garnet or Malaya garnet is a gemology gemological varietal name for light to dark slightly pinkish orange, reddish orange, or yellowish orange garnet , that are of a mixture of pyrope , and spessartite . It is found in east Africa , in the Umba Valley bordering Tanzania and Kenya . ref http www.geo.utexas.edu courses 347k redesign gem notes garnet garnet main.htm Garnet Almandine, Rhodolite, Pyrope, Demantoid, Tsavorite, Hessonite, Grossular, Spessartine Course notes at the Department of Geological Sciences, The University of Texas at Austin website, accessed January 27, 2007 ref References Reflist Category Cubic minerals Category Gemstones Mineral stub ... more details
Taxobox name Xolmis image NOIVINHA BRANCA Xolmis velatus .jpg image caption White rumped Monjita regnum Animalia phylum Chordata classis Bird Aves ordo Passeriformes familia Tyrannidae genus Xolmis genus authority Friedrich Boie F. Boie , 1826 subdivision ranks Species subdivision see text synonyms Heteroxolmis Xolmis is a genus of bird in the Tyrannidae family. It contains the following species Fire eyed Diucon Xolmis pyrope Grey Monjita Xolmis cinereus Black crowned Monjita Xolmis coronatus White rumped Monjita Xolmis velatus White Monjita Xolmis irupero Black and white Monjita Xolmis dominicanus Rusty backed Monjita Xolmis rubetra Salinas Monjita Xolmis salinarum Category Xolmis Category Genera of birds Tyrannidae stub ca Xolmis es Xolmis fr Xolmis hu Xolmis nl Xolmis pl Xolmis ru fi Monhiitat ... more details
infobox mineral name Knorringite category Silicate mineral image imagesize alt caption formula Mg sub 3 sub Cr sub 2 sub SiO sub 4 sub sub 3 sub strunz 09.AD.25 dana symmetry Isometric hexoctahedral 4 m overline 3 2 m unit cell a 11.59 Z 8 molweight color Bluish green colour habit Massive and as minute grains system Cubic crystal system Cubic twinning cleavage None fracture tenacity mohs 6 7 luster Vitreous streak diaphaneity Semitransparent gravity 3.756 density polish opticalprop Isotropic refractive n 1.803 birefringence pleochroism 2V dispersion extinction length fast slow fluorescence absorption melt fusibility diagnostic solubility impurities alteration other references ref name Mindat http www.mindat.org min 2229.html Mindat.org ref ref name HBM http rruff.geo.arizona.edu doclib hom knorringite.pdf Handbook of Mineralogy ref ref name Webmin http www.webmineral.com data Knorringite.shtml Webmineral description ref Knorringite is a mineral species belonging to the garnet group, and forms a series with the species pyrope . It was discovered in 1968 in the Kao kimberlite pipe in the Butha Buthe District of Lesotho and is named after Oleg Von Knorring , a professor of mineralogy at the University of Leeds in England . ref name Mindat ref name HBM Synthetic knorringite has the pure endmember formula Mg sub 3 sub Cr sub 2 sub SiO sub 4 sub sub 3 sub . ref name HBM As knorringite is a member of the knorringite pyrope series, natural samples contain variable aluminium in the chromium site. ref http www.minsocam.org ammin AM53 AM53 1833.pdf Nixon, P.H. and G. Hornung 1968 A new chromium garnet end member, knorringite, from kimberlite, Amer. Mineral., 53, 1833 1840 ref Knorringite is a greenish blue color with a Mohs scale of mineral hardness of six to seven. It occurs as a rare component within ultramafic nodules in kimberlites in association with olivine , enstatite , chrome diopside , chromian pyrope, chromian spinel , ilmenite , perovskite , zircon , diamond , omp ... more details
Flinders Island is an island in the Investigator Group off the coast of South Australia . It was named by Matthew Flinders after his younger brother Samuel Flinders, a midshipman on HMS Investigator 1798 HMS Investigator in 1801. ref gutenberg no 7304 name The Life of Captain Matthew Flinders author Ernest Scott ref It is part of the Investigator Group Important Bird Area . ref name bli BirdLife International. 2011 . Important Bird Areas factsheet Investigator Islands. Downloaded from http www.birdlife.org on 12 07 2011. ref The island has been subject to diamond exploration following the discovery of a wide range of kimberlite indicator minerals there. ref Cooper, S.A., 2004. New diamond field discovered in SA. MESA Journal 24, 6 9. http www.pir.sa.gov.au dhtml ss section.php?sectID 972 Primary Industries & Resources South Australia publication. ref These minerals include chromite, pyrope, diopside, picroilmenite, forsterite, orthopyroxene, as well as small diamonds. References reflist Eyre Peninsula coord 33 43 S 134 29 E display title Category Important Bird Areas of South Australia Category Eyre Peninsula Category Islands of South Australia SouthAustralia geo stub fr Flinders Island Investigator zh classical ... more details
Unreferenced date December 2009 Image Almandine.jpeg thumb An almandine garnet growing as a porphyroblast in a quartzite quartzitic gneiss . The garnet measures 3 cm. Location Para ba , Brazil . Image Peridotite with pyrope porphyroblasts.JPG thumb Purple pyrope porphyroblasts in a peridotite , 1 euro coins coin of 1 euro for scale. The yellow brown matrix geology groundmass is weathering weathered olivine . Location Otr y , Western Gneiss Region , Caledonides , Norway . A porphyroblast is a large mineral crystal in a metamorphic rock which has grown within the finer grained Matrix geology groundmass . Porphyroblasts are commonly euhedral crystals, but can also be partly to completely irregular in shape. The most common porphyroblasts in meta pelite s metamorphosed mudstone s and siltstone s are garnet s and staurolite s, which stand out in well Foliation geology foliated metapelites such as schist s against the platy mica matrix. A similar type of crystal is a phenocryst , a large crystal in an igneous rock . Porphyroblasts are often confused with porphyroclast s , which can also be large outstanding crystals, but which are older than the matrix of the rock. A rock which has many porphyroblasts is described as having a porphyroblastic texture . As porphyroblasts grow, the foliation may be preserved as oriented inclusions trapped by the porphyroblast as it overgrows them, and this is helpful for tracking changing deformation planes. In metamorphic rocks that experience deformation during metamorphism, porphyroblasts may grow before, during, or after the phase of deformation recorded by the matrix minerals. The relationship of porphyroblast growth to deformation is typically evaluated by comparing the shape orientation of trails of mineral inclusions in the porphyroblast to the matrix fabric. Some garnet porphyroblasts contain various curving trails of quartz and other mineral inclusions. The question of whether porphyroblasts and garnet in particular rotate during m ... more details
4.3 melt fusibility diagnostic solubility diaphaneity other var1 Pyrope var1text Mg sub 3 sub Al sub ... compositions. The different species are pyrope , almandine , spessartine , grossular varieties ... up two solid solution series pyrope almandine spessarite and uvarovite grossular andradite. Physical ... aluminium in Y site Almandine Fe sub 3 sub Al sub 2 sub SiO sub 4 sub sub 3 sub Pyrope Mg sub 3 sub .... PyropePyrope from the Greek pyr p s meaning fire eyed is red in color and chemically a magnesium ... the magnesium can be replaced in part by calcium and ferrous iron. The color of pyrope varies from deep red to almost black. Pyrope and spessartine gemstones have been recovered from the Sloan diamondiferous ... location Laramie, Wyoming pages 268 p. ref A variety of pyrope from Macon County, North Carolina Macon ... a rose. In chemical composition it may be considered as essentially an isomorphous mixture of pyrope and almandine, in the proportion of two parts pyrope to one part almandine. Pyrope has tradenames ... from Madagascar, a pyrope spessartine mix. The color of these blue garnets is not like sapphire ... light. cn date March 2012 Pyrope is an indicator mineral for high pressure rocks. The garnets from Earth s mantle mantle derived rocks, peridotite s and eclogite s, commonly contain a pyrope ... never occurs in nature. Pyrope rich in the knorringite component is only formed under high pressure ... sub Fe sup 2 sup Ti sup 4 sup SiO sub 4 sub sub 3 sub isometric m overline 3 m Ia overline 3 d Pyrope ... composition, but mainly consisting of garnet and omphacite . Pyrope rich garnet is restricted ... s mantle. Peridotite may contain plagioclase , or aluminium rich spinel, or pyrope rich ... more details
Image Etang de lers lherzolite.jpg thumb right 250px Lherzolite at Etang de Lers, Ari ge, France Image Lherzolite eifel.jpg thumb right 250px Lherzolite xenolith from Eifel , Germany Lherzolite is a type of ultramafic igneous rock . It is a coarse grained rock consisting of 40 to 90 olivine along with significant orthopyroxene and lesser calcic chromium rich clinopyroxene . Minor minerals include chromium and aluminium spinel s and garnet s. Plagioclase can occur in lherzolites and other peridotite s that crystallize at relatively shallow depths 20 30 km . At greater depth plagioclase is unstable and is replaced by spinel. At approximately 90 km depth, pyrope garnet becomes the stable aluminous phase. Garnet lherzolite is a major constituent of the Earth s upper mantle extending to 300 km depth . Lherzolite is known from the lower ultramafic part of ophiolite complexes although harzburgite is more common in this setting , from alpine type peridotite massifs, from fracture zones adjacent to mid oceanic ridges, and as xenolith s in kimberlite pipes and alkali basalts. Partial melting of spinel lherzolite is one of the primary sources of basalt ic magma . The name is derived from the Lherz Massif , an alpine peridotite complex also known as orogenic lherzolite complex , the type locality at Etang de Lers, near Massat in the France French Pyrenees Lherz is the archaic spelling of this location. The Lherz massif also contains harzburgite and dunite , as well as layers of spinel pyroxenite , garnet pyroxenite, and hornblendite . The layers represent partial melts extracted from the host peridotite during decompression in the Mantle geology mantle long before emplacement into the crust. The Lherz massif is unique because it has been emplaced into Paleozoic carbonates limestone s and dolostone s , which form mixed breccia s of limestone lherzolite around the margins of the massif. References Blatt, Harvey and Robert J. Tracy, 1996, Petrology Igneous, Sediment ... more details
Orphan date March 2012 The Lake Ellen Kimberlite is a poorly exposed volcanic breccia located about 10 miles northeast of Crystal Falls, Michigan . The first publication in 1981 ref Cannon, W., Murdrey, M. 1981 The Potential for Diamond Bearing Kimberlite in Northern Michigan and Wisconsin , U. S. Geological Survey Circular No. 842. ref describing the feature led to speculation that this or similar kimberlites in the area might have been the source of the diamonds discovered a century before in Wisconsin as well as a period of exploration by several minerals firms. File LakeEllenKimberlite.jpg thumb Typical weathered kimberlite from the Lake Ellen occurrence The kimberlite was discovered in 1971 when a logging road was bulldozed through the area exposing the unusual looking rock. The exposure consists of several small areas otherwise overlain by glacial till. Magnetic survey work done in 1956 ref Gair, J. E., and Wier, K. L., 1956, Geology of the Kiernan Quadrangle, Iron County, Michigan U.S. Geological Survey Bulletin 1044, 88 p ref depicts an elliptical positive anomaly 180 m 590 ft long in an east west direction and 120 m 390 ft wide which probably defines the limits of the pipe. The kimberlite is intruded into volcanic rocks of the Proterozoic Hemlock Formation. The exposed material is grayish green to redish, iron stained highly weathered and consists of disaggregated rubbly fragments up to 25 cm 10 in . It is generally accepted that the pipe was emplaced about 180 my ago. The lake Ellen Kimberlite has become widely known in recent years and is popular with rock hounds as the classic indicator minerals Pyrope , Magnesian Ilmenite and Chrome Diopside for kimberlite are easily found in the material though few are of gem quality and size. While there was considerable interest in diamond exploration in Michigan s Upper Peninsula and northern Wisconsin for several years no diamonds of commercial interest have been found. See also Kimber ... more details
powers of healing and divination. When the habit Pyrope raises water taxes and conscripts ... the taxation and the conscription. Pyrope, noticing her beauty, makes a deal with her no more water .... During that time, she comes to fall in love with Pyrope, though he infuriates her with his lewdness ... she tried her very best not to fall in love with him. When Diamond infiltrates the city, she and Pyrope ... to risk her, Pyrope becomes seriously injured before killing all the guards. Seeing Pyrope slowly ... is pregnant with Pyrope s child. In the meantime, Lapis comes to rescue her, even as Diamond comes charging in. Pyrope stays behind to guard their escape and is killed by Diamond. At his death, Silica ... for the sake of her and Pyrope s son. She does come back to help harden Lapis s resolve with a chilling ... the twelve Mines, as well as manipulating both Lapis and Ivory. Pyrope The ruler of the desert Mine of Sable, Pyrope is a young, attractive man with brilliant red hair and a notorious love of bloodshed ... more details
mineral assemblage of forsteritic olivine , magnesian ilmenite , chromium pyrope , almandine pyrope ..., pyrope , chromian diopside, magnesian ilmenite and phlogopite, in a fine to medium grained groundmass ... forsteritic olivine , pyrope garnet, Cr diopside , magnesian ilmenite and spinel . Group II ... a pyroxene , chromium spinels, magnesian ilmenite, and garnets rich in pyrope plus chromium, are generally ... more details
Refimprove date March 2012 Distinguish amandine disambiguation Infobox mineral name Almandine category Nesosilicate boxwidth boxbgcolor image Almandin.jpg imagesize 300px caption formula Fe sup 2 sup sub 3 sub Al sub 2 sub Si sub 3 sub O sub 12 sub strunz 09.AD.25 molweight color reddish orange to red, slightly purplish red to reddish purple and usually dark in tone habit system twinning cleavage none fracture conchoidal ref name GRG mohs 7 7.5 luster greasy to vitreous polish vitreous to subadamantine ref name GRG refractive 1.790 .030 ref name GRG Gemological Institute of America , GIA Gem Reference Guide 1995, ISBN 0 87311 019 6 ref opticalprop Single refractive, and often anomalous double refractive ref name GRG birefringence none dispersion .024 ref name GRG pleochroism none fluorescence inert absorption usually at 504, 520, and 573nm, may also have faint lines at 423, 460, 610 and 680 690nm ref name GRG streak gravity 4.05 .25, .12 ref name GRG density melt fusibility diagnostic solubility diaphaneity other Almandine IPAc en icon l m n d n , also known incorrectly as almandite , is a species of mineral belonging to the garnet group. The name is a corruption of alabandicus, which is the name applied by Pliny the Elder to a stone found or worked at Alabanda, a town in Caria in Asia Minor . Almandine is an iron alumina garnet, of deep red color, inclining to purple. It is frequently cut with a convex face, or en cabochon , and is then known as Carbuncle gemstone carbuncle . Viewed through the spectroscope in a strong light, it generally shows three characteristic absorption bands. Almandine is one Endmember mineralogy end member of a mineral solid solution series, with the other end member being the garnet pyrope . The almandine crystal formula is Fe sub 3 sub Al sub 2 sub SiO sub 4 sub sub 3 sub . Magnesium substitutes for the iron with increasingly pyrope rich composition. Almandine, Fe sup 2 sup sub 3 sub Al sub 2 sub Si sub 3 sub O sub 12 sub , is the ... more details
distinguish Dunnite Image Basanite&Dunite bomb.JPG thumb right 250px Small volcanic bomb of black basanite with green dunite Dunite IPAc en icon d n a t or IPAc en dj u n a t is an igneous rock igneous , plutonic rock geology rock , of ultramafic composition, with coarse grained or phaneritic texture. The mineral assemblage is greater than 90 olivine , with minor amounts of other minerals such as pyroxene , chromite and pyrope . Dunite is the olivine rich end member of the peridotite group of mantle derived rocks. Dunite and other peridotite rocks are considered the major constituents of the Earth s Mantle geology mantle above a depth of about 400 kilometers. Dunite is rarely found within continental rocks, but where it is found, it typically occurs at the base of ophiolite sequences where slabs of mantle rock from a subduction zone have been thrust onto continental crust by obduction during continental or island arc collisions orogeny . It is also found in alpine peridotite massifs that represent slivers of sub continental mantle exposed during collisional orogeny. Dunite typically undergoes retrograde metamorphism in near surface environments and is altered to serpentinite and soapstone . Dunite may represent the refractory residue left after the extraction of basalt ic magma s in the upper mantle. This is the type of dunite found in the lowermost parts of ophiolites, alpine peridotite massifs, and xenolith s. Dunite may also form by the accumulation of olivine crystals on the floor of large basaltic or Picrite picritic magma chambers. These Cumulate rock cumulate dunites typically occur in thick layers in layered intrusion s, associated with cumulate layers of wehrlite , olivine pyroxenite , harzburgite , and even chromitite a cumulate rock consisting largely of chromite . Small layered intrusions may be of any geologic age, for example, the Triassic Palisades Sill in New York and the larger Eocene Skaergaard complex in Greenland. The largest layered maf ... more details
File coesite.png 150px thumb Atomic structure of coesite Coesite References sup p sup is a form Polymorphism materials science polymorph of silicon dioxide silicon Si oxygen O sub 2 sub that is formed when very high pressure 2&ndash 3 gigapascal s , and moderately high temperature convert 700 C F disp or sigfig 2 , are applied to quartz . Coesite was first synthesized by Loring Coes, Jr. , a chemist at the Norton Company , in 1953. ref name C53 cite journal last Coes first L., Jr. date 31 July 1953 title A New Dense Crystalline Silica journal Science volume 118 issue 3057 pages 131 132 url http www.sciencemag.org cgi pdf extract 118 3057 131 doi 10.1126 science.118.3057.131 pmid 17835139 bibcode 1953Sci...118..131C ref ref Hazen, Robert M. 1999 . The diamond makers . New York Cambridge University Press. ref In 1960, coesite was found by Edward C. T. Chao , ref cite journal doi 10.1126 science.132.3421.220 title First Natural Occurrence of Coesite year 1960 last1 Chao first1 E. C. T. last2 Shoemaker first2 E. M. last3 Madsen first3 B. M. journal Science volume 132 pages 220 2 pmid 17748937 issue 3421 bibcode 1960Sci...132..220C ref in collaboration with Eugene Shoemaker , to naturally occur in the Barringer Crater , which was evidence that the crater must have been formed by an impact. The presence of coesite in unmetamorphosed rocks may be evidence of a meteorite impact event or of an atomic bomb explosion. In metamorphic rocks, coesite commonly is one of the best mineral indicators of metamorphism at very high pressures UHP, or ultrahigh pressure metamorphism . ref cite journal doi 10.1007 BF00381838 title Coesite and pure pyrope in high grade blueschists of the Western Alps a first record and some consequences year 1984 last1 Chopin first1 Christian journal Contributions to Mineralogy and Petrology volume 86 pages 107 bibcode 1984CoMP...86..107C issue 2 ref Such UHP metamorphic rocks record subduction or continental collisions in which crustal rocks are carried to ... more details
is garnet pyrope to almandine plus clinopyroxene omphacite . Eclogites record pressures in excess ... diamonds. Harzburgitic diamonds typically have titaniferous pyrope , chromian spinel and Cr diopside ... more details
Semireg dual polyhedra db Semireg dual polyhedron stat table dCO In geometry , the rhombic dodecahedron is a Convex polyhedron convex polyhedron with 12 congruence congruent rhombus rhombic faces. It is an Archimedean solid Archimedean dual solid, or a Catalan solid . Its Dual polyhedron dual is the cuboctahedron . Properties The rhombic dodecahedron is a zonohedron . Its polyhedral Dual polyhedron dual is the cuboctahedron . The long diagonal of each face is exactly Square root of two 2 times the length of the short diagonal, so that the Angle Types of angles acute angles on each face measure arccos 1 3 , or approximately 70.53 . Being the dual of an Archimedean solid Archimedean polyhedron , the rhombic dodecahedron is face transitive , meaning the symmetry group of the solid acts transitive action transitively on the set of faces. In elementary terms, this means that for any two faces A and B there is a rotation or Reflection mathematics reflection of the solid that leaves it occupying the same region of space while moving face A to face B. The rhombic dodecahedron is one of the nine edge transitive convex polyhedra, the others being the five Platonic solid s, the cuboctahedron , the icosidodecahedron and the rhombic triacontahedron . File Grenat pyrope 1 .jpg thumb left 120px A garnet crystal The rhombic dodecahedron can be used to Tessellation tessellate three dimensional space. It can be stacked to fill a space much like hexagon s fill a plane. This tessellation can be seen as the Voronoi tessellation of the Crystal structure face centered cubic lattice . Some minerals such as garnet form a rhombic dodecahedral crystal habit . Honeybee s use the geometry of rhombic dodecahedra to form honeycomb from a tessellation of cells each of which is a hexagonal prism capped with half a rhombic dodecahedron. The rhombic dodecahedron also appears in the unit cells of diamond and diamondoid s. In these cases, four vertices are absent, but the chemical bonds lie on the rema ... more details
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