Calcite Taw Qhia

Calcite yog calcium carbonate ntxhia, thiab nws yog cov feem ntau hom calcium carbonate. Yog li ntawd, calcite yog ib qho khoom siv dav dav. Calcite crystals tuaj nyob rau hauv ntau yam duab; lawv cov aggregates tuaj yeem yog pawg ntawm cov muaju, los yog lawv tuaj yeem ua tau granular, loj, fibrous, stalactitic, earthy, thiab lwm yam. Kev tawg calcite ua rau ntau lub rhombohedral tawg, yog li lub npe "calcite." Cov xim ntawm calcite txawv nyob ntawm qhov impurities nws muaj; Piv txwv li, thaum nws muaj hlau thiab manganese, nws yog lub teeb daj, lub teeb liab, xim av -dub, thiab lwm yam. Txawm li cas los xij, nws feem ntau yog dawb lossis tsis muaj xim. Tsis muaj xim thiab pob tshab calcite kuj hu ua Iceland spar. Hom calcite no muaj cov yam ntxwv zoo tshaj plaws: nws cov birefringence yog siab li 0.172, tso cai rau cov khoom tshwm sim ua ob daim duab. Yog li ntawd, Iceland spar yog cov khoom siv kho qhov muag tseem ceeb. Calcite yog cov ntxhia tseem ceeb hauv limestone thiab marble, thiab nws muaj ntau yam siv hauv kev tsim khoom thiab lub neej txhua hnub, nws qhov tseem ceeb tshaj plaws yog siv hauv kev tsim cov cement. Limestone tuaj yeem tsim cov qhov tsua, thiab cov stalactites, stalagmites, thiab lwm yam tsim hauv cov qhov tsua no yog tsim los ntawm calcite. Calcite feem ntau muaj cov isomorphous hloov pauv xws li Mn, Fe, Zn, Mg, Pb, Sr, Ba, thiab Co; Thaum cov tshuaj no ncav cuag ib qho nyiaj, lawv tuaj yeem tsim ntau yam xws li manganese calcite, hlau calcite, zinc calcite, thiab magnesium calcite. Tsis tas li ntawd, txhua yam impurities xws li brucite, dolomite, hlau hydroxides thiab oxides, sulfides, thiab quartz feem ntau pom muaj nyob rau hauv cov muaju. Nws belongs rau trigonal crystal system; zoo- cov crystals tsim muaj ntau. Nws nthuav tawm ntau yam morphologies, nrog ntau dua 600 qhov sib txawv. Nws feem ntau tshwm sim raws li cov kab sib luag thiab cov kab sib txuas tabular, thiab ntau lub xeev ntawm rhombohedral lossis ditrigonal triangular-faceted crystals. Calcite feem ntau ua rau cov menyuam ntxaib, thiab ntau dua li cov menyuam ntxaib polysynthetic. Kev taw qhia ntawm cov kab sib txuas polysynthetic ntawm cov dav hlau cleavage txawv ntawm dolomite. Nyob rau hauv qhov xwm txheej, cov tsos ntawm cov menyuam ntxaib polysynthetic tuaj yeem qhia tau tias calcite tau dhau los ntawm kev ntxhov siab geological tom qab nws tsim.