Talc (3MgO.4SiO2.H2O)

It is an important source of MgO flux for bodies and glazes. Dolomite and magnesium carbonate have high loss on ignitions which can produce glaze bubbles, blisters and pinholes, talc is much less of a problem in this respect. High temperature magnesia matte glazes employ MgO from talc and magnesium carbonate to form magnesium silicate crystals on cooling to give both opacity and a matte silky surface.

Mixture Al2O3 CaO Fe2O3 MgO Na2O+K2O SiO2 ZŽ (ztráta žíháním)
Talc 1% 1% max 0,7% 31,5% 0,2% 59,2% 6,5%

back to materials list