A composition of a ceramic layer for manufacturing a casting mould and other products, in particular intended for making castings by investment casting, comprising a liquid ceramic mass consisting of, in weight %, 50-75% of a ceramic material which is a mixture with particle-size distribution comprising minimum 90% of particles of size less than 0.04 mm, having the following phase composition: 30-90% of forsterite Mg2SiO4, 5-15% of fayalite Fe2SiO4 and 5-65% of a mixture of phase components such as chrysolite 2(Mg0,88Fe0,12)SiO2, enstatite MgSiO3, tremolite Ca2Mg5Si8O22(OH)2, ringwoodite (Mg,Fe)2, diopside Ca(Mg,AI)(Si,AI)2O6 and others, and of 25-50% of a binder comprising an aqueous or aqueous-organic colloidal solution of a metallic oxide and modifiers, and a ceramic material for sprinkling which is a mixture having the following phase composition, in weight %: 30-90% of forsterite Mg2SiO4, 5-15% of fayalite Fe2SiO4, and 5-65% of a mixture of phase components such as chrysolite 2(Mg0,88Fe0,12)SiO2, enstatite MgSiO3, tremolite Ca2Mg5Si8O22(OH)2, ringwoodite (Mg,Fe)2, diopside Ca(Mg,AI)(Si,Al)2O6 and others.