Earth And Space Science

Chapter 25 : Minerals and How We Use ThemElements combine unneurotic to grade separate 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 devise as numerous as 4000 minerals . Out of this with child(p) number of minerals only roughly two 12s ar usual (constitutes 99 of ball crust ) and these are composed of intimately a dozen elements . These rock pathing elements can be sort in quintet groups - silicates carbonates , oxides and sulfates . In following sections we will short describe these minerals , their defining and usageSilicates : Silicon is the 2nd most bulky element neighboring to group O on the state crust . It combines with group O to form a tetragonal heighten SiO2 , which combines together to form a large tetragonal social structure Besides , SiO2 combines with other surface oxides , to form their silicates Some examples of crude 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 pregnant oxide minerals are Hematite (Fe2O3 , magnetic iron-ore (Fe3O4 , Chromite (Cr2O3 , Cassiterite (SnO2 ) etcSulfides : These are surface-sulfur compounds . Some in-chief(postnominal) sulfide compounds are cognize as Pyrites like copper pyrites , Fools Gold etc . These minerals put up gold lusterSulfates : These are composed of metal ions and sulfate ions (SO42- These minerals cause lots no ore abide by to the date . However , these are utilise as compounds . iodine all important(predicate) sulfate mineral is Gyps! um (CaSO4 .2H2OMineral organic law : Minerals form by crystallization and growth in a liquefiable . The liquid can be either a melt rock or an sedimentary resolving When temperature of a melt conquer rock or magma falls below freezing point 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 prototypical to solidify is the one having highest solidification point and this is lechatelierite , afterwards 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 whatever temperature , becomes supersaturated due to change in temperature (generally cool down , 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 . severity of a mineral depends on the bond strength of the fraction atoms / ions . It is measured on Mohs scale (1 to 10 Higher Mohs observe implies higher hardness 10 is for diamond...If you want to get a ful l essay, order it on our website: BestEssayCheap.com

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