MineralGroups‐SilicatesandCarbonates
EarthScience–2ndSemester
• Mineralscanbeclassifiedintogroupsbasedontheircomposi;on.
Silicates
• Thetwomostabundantmineralsinearth’scon6nentalcrustaresiliconandoxygen.
• Thesetwoelementscombinetoformanewstructurecalledthesilicon–oxygentetrahedron.
• Thetetrahedronconsistsofonesiliconatomandfouroxygenatoms.
• Itprovidestheframeworkforeverysilicatemineral,
Ex.Quartz.
• Theinternalstructureoftheatomswillaffecttheproper6esoftheatom.
• Example:Olivine–veryhardmineral,madefrommillionsoftetrahedronbondedtogether.
• Mica–thetetrahedronjointogethertoformsheets.
• Quartz–Formedbythree‐dimensionalnetworksoftetrahedron
• Silicatemineralscrystallizefrommagmaasitcools.
• Thetypeofmineralthatformsisaresultofthepressureandtemperatureoftheenvironmentofforma;on.
• Example:Olivinewillcrystallizeattemperaturesofabout1200°C,undergreatpressurebelowthesurface.
• Quartzwillcrystallizeat700°Cclosetothesurface.
• Silicatemineralssuchasclaymineralscanformatthesurfacewhenexposedtotheelementsandbrokendown,aprocessknownasweathering.
• Somesilicatemineralsonlyformfromthepressurecausedbytectonicplatesgrindingtogethertobuildmountains.
• GeologistsoSenusesilicatemineralsasevidencetotellthemunderwhatcondi;onsthemineralformedunder.
• Thisinturncanhelpgeologiststodeterminehowtheplanetlookedmillionsofyearsago.
Carbonates
• Secondmostcommonmineralgroup.
• Thesearemineralsthatcontaintheelementscarbon,oxygen,andoneormoremetallicelements.
• Ex.calcite
• Dolomite–magnesiumandcalcium
• Thesemineralsarefoundintherockslimestoneandmarble,whichareusedheavilyinconstruc;onandbuilding.