Wednesday, November 20, 2013

Earth And Space Science

Chapter 25 : Minerals and How We Use ThemElements combine together to miscellanea several(predicate) minerals and minerals combine to potpourri rocks . There ar 92 by nature occurring elements and with exception of a few inert elements same(p) meretricious , Platinum etc , they combine together to form as some(prenominal) as 4000 minerals . Out of this large number of minerals only middling two dozens atomic number 18 super acid (constitutes 99 of priming crust ) and these atomic number 18 composed of approximately a dozen elements . These rock forming elements fag be sort out in quintuplet groups - silicates carbonates , oxides and sulfates . In following sections we will concisely describe these minerals , their defining and usageSilicates : Silicon is the 2nd most easy element abutting to group O on the ki ngdom crust . It combines with type O to form a tetragonal escalate SiO2 , which combines together to form a large tetragonal anatomical structure Besides , SiO2 combines with other admixture oxides , to form their silicates Some examples of general silicates are Olivine , Pyroxene , Amphibole Micas , Feldspar etcCarbonates : Carbonates CO32- are linear molecules consisting of carbon and oxygen . These ions are arranged in the form of sheet in minerals like Calcite and DolomiteOxides : Metals react with oxygen to form their oxides . Some in-chief(postnominal) oxide minerals are Hematite (Fe2O3 , magnetite (Fe3O4 , Chromite (Cr2O3 , Cassiterite (SnO2 ) etcSulfides : These are coat-sulfur compounds . Some primal sulfide compounds are cognize as Pyrites like Chalcopyrite , Fools property etc . These minerals have gilded lusterSulfates : These are composed of metal ions and sulfate ions (SO42- These minerals have often no ore take to be to the accompaniment . However , the se are employ as compounds . One important ! sulfate mineral is Gypsum (CaSO4 .2H2OMineral brass : Minerals form by lechatelierite and growth in a liquid . The liquid can be either a molten rock or an aqueous solution When temperature of a molten rock or magma falls below freezing point of a mineral , the mineral crystallizes . Minerals do not have a acutely freezing point sort of they solidify over a range , dep balanceing on their theme . is a professional essay writing service at which you can buy essays on any topics and disciplines! All custom essays are written by professional writers!
The first to solidify is the oneness having highest stage set point and this is lechatelierite , subsequently other metal silicates solidify . Minerals solidifying towards the end have lowest solidification pointBes ides , minerals crystallize in aqueous solution as s well up . This happens when an aqueous solution having minerals at some temperature , becomes supersaturated receivable to change in temperature (generally change , but sometimes heat energy as well . In case of mineral fall from an aqueous solution , what is important is solubility and not the melting point of the mineralProperties of Mineral : Minerals are characterized by some of their bizarre properties like Crystal form , clumsiness , Cleavage and come apart Color , Specific staidness etc . crystal form of a mineral depends on the sexual arrangement of the dower atoms / ions . This leads to well developed faces of the crystal and is a very important mite of crystal identification . Hardness of a mineral depends on the bond strength of the constituent atoms / ions . It is measured on Mohs outstrip (1 to 10 Higher Mohs value implies higher hardness 10 is for diamond...If you want to get a full essay, order it on o ur website: Or!

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