[Chemical composition] MgO 31.72%, SiO2 63.52%, H2O 4.76%. It also often contains FeO, up to 2-5%. Further, it also contains Al, Mn, Ca, and Ni.
[Form] Monoclinic system. Crystals are rare, often in the form of flaky scaly or dense block aggregates.
[Physical properties] White, but often with light green, light brown, light yellow and other colors. Glass luster, dense block often with waxy luster, with pearl luster inside. Hardness 1. Slip cleavage sheet is flexible. The proportion is 2.7-2.8.
[Genesis and occurrence] Talc is mainly formed by hydrothermal alteration of magnesium- rich rocks such as ultrabasic rocks and dolomite . The olivine in the ultrabasic rocks and the dolomite in the dolomite can form talc by hydrothermal alteration.
4(Mg,Fe) 2 (SiO 4 )+H 2 O+CO 2 →Mg 3 [Si 4 O 10 ](OH) 2 +Mg[CO 3 ]+Fe 2 O 3
Olivine talc magnesite
3CaMg[CO 3 ] 2 +4SiO 2 +H 2 O→Mg 3 [Si 4 O 10 ](OH) 2 +3Ca[CO 3 ]+CO 2
Dolomite talc calcite
In addition, talc, such as talc schist, can also be formed during regional metamorphism.
[Identification Features] Features low hardness, slipperiness, light color, flake shape, and a set of extremely complete cleavage.
Needle Roller Bearings,Needle Bearing Hk2016,Open Type Bearings Hk2020,Needle Roller Bearing Pin
UKL Bearing Manufacturing Co., Ltd., , https://www.bearingukl.com