Earth And Space Science

Chapter 25 : Minerals and How We Use ThemElements combine together to grade severalise minerals and minerals combine to diversity rocks . There atomic number 18 92 by nature occurring elements and with exception of a hardly a(prenominal) inert elements like funds , Platinum etc , they combine together to defecate as numerous as 4000 minerals . Out of this tumescent number of minerals only roughly two 12s ar grossplace (constitutes 99 of ball crust ) and these are composed of to the highest degree a dozen elements . These rock habitusing elements can be assort in quintet groups - silicates carbonates , oxides and sulfates . In following sections we will presently describe these minerals , their defining and usageSilicates : Silicon is the 2nd most immense element neighboring to group O on the undercoat crus t . It combines with oxygen to form a tetragonal enhance SiO2 , which combines together to form a large tetragonal social organisation Besides , SiO2 combines with other surface oxides , to form their silicates Some examples of common 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 meaning(a) oxide minerals are Hematite (Fe2O3 , magnetic iron-ore (Fe3O4 , Chromite (Cr2O3 , Cassiterite (SnO2 ) etcSulfides : These are admixture-sulfur compounds . Some historic sulfide compounds are cognize as Pyrites like copper pyrites , Fools Gold etc . These minerals pay off gold lusterSulfates : These are composed of metal ions and sulfate ions (SO42- These minerals micturate lots no ore abide by to the date . However , these are utilise as compounds . unmatched important sulfate m! ineral is Gypsum (CaSO4 .2H2OMineral organic law : Minerals form by crystallization and growth in a smooth-spoken . The liquid can be either a resolve rock or an sedimentary declaration When temperature of a liquefied rock or magma falls below freezing plosive consonant of a mineral , the mineral crystallizes . Minerals do not have a sharp freezing point preferably they change integrity over a range , dep conclusioning on their composing .

The firstly to solidify is the one having highest solidification point and this is lechatelierite , afterward other metal silicates solidify . Minerals solidifying towards the end have lowest solidification pointBesides , minerals crystallize in aqueous solution as well . This happens when an aqueous solution having minerals at round temperature , becomes supersaturated due to change in temperature (generally cool subject , but sometimes heating as well . In case of mineral precipitation 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 unique properties like Crystal form , callosity , Cleavage and Fracture Color , Specific solemnity etc . crystal form of a mineral depends on the indispensable arrangement of the parting atoms / ions . This leads to well developed faces of the crystal and is a very important clue of crystal identification . rigor of a mineral depends on the bond strength of the dower atoms / ions . It is measured on Mohs scale (1 to 10 Higher Mohs place implies higher hardness 10 is for diamond...If you want to get a full essay, order it on our website: BestEssayCheap.com

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