A composition of a ceramic layer for manufacturing a casting mould, in particular intended for making castings by investment casting, comprising: a) a liquid ceramic mass and b) a ceramic material for sprinkling - characterized in that the composition comprises: a1) the liquid ceramic mass consisting of, in weight %, 50 - 75% of the ceramic material which is a mixture with particle-size distribution comprising minimum 90% of particles of size less than 0.04 mm, and the following phase composition: 30 - 90% of forsterite Mg 2 SiO 4, 5 - 15% of fayalite Fe 2 SiO 4 and 5 - 65% of a mixture of phase components such as chrysolite 2(Mg 0.88 Fe 0.12)SiO 2, enstatite MgSiO 3, tremolite Ca 2 Mg 5 Si 8 O 22 2, ringwoodite (Mg,Fe) 2 [SiO 4] and diopside Ca(Mg,Al)(Si,Al) 2 O 6, and a2) 25 - 50% of a binder comprising an aqueous or aqueous-organic colloidal solution of a metallic oxide and modifiers, and b1) the ceramic material for sprinkling which is a mixture having the following phase composition, in weight %: 30 - 90% of forsterite Mg 2 SiO 4, 5 - 15% of fayalite Fe 2 SiO 4, and 5 - 65% of a mixture of phase components such as chrysolite 2(Mg 0.88 Fe 0.12)SiO 2, enstatite MgSiO 3, tremolite Ca 2 Mg 5 Si 8 O 22 2, ringwoodite (Mg,Fe) 2 [SiO 4] and diopside Ca(Mg,Al)(Si,Al) 2 O 6. a) a liquid ceramic mass and b) a ceramic material for sprinkling - characterized in that the composition comprises: a1) the liquid ceramic mass consisting of, in weight %, 50 - 75% of the ceramic material which is a mixture with particle-size distribution comprising minimum 90% of particles of size less than 0.04 mm, and the following phase composition: 30 - 90% of forsterite Mg 2 SiO 4, 5 - 15% of fayalite Fe 2 SiO 4 and 5 - 65% of a mixture of phase components such as chrysolite 2(Mg 0.88 Fe 0.12)SiO 2, enstatite MgSiO 3, tremolite Ca 2 Mg 5 Si 8 O 22 2, ringwoodite (Mg,Fe) 2 [SiO 4] and diopside Ca(Mg,Al)(Si,Al) 2 O 6, and a2) 25 - 50% of a binder comprising an aqueous or aqueous-organic colloidal solution of a metallic oxide and modifiers, and b1) the ceramic material for sprinkling which is a mixture having the following phase composition, in weight %: 30 - 90% of forsterite Mg 2 SiO 4, 5 - 15% of fayalite Fe 2 SiO 4, and 5 - 65% of a mixture of phase components such as chrysolite 2(Mg 0.88 Fe 0.12)SiO 2, enstatite MgSiO 3, tremolite Ca 2 Mg 5 Si 8 O 22 2, ringwoodite (Mg,Fe) 2 [SiO 4] and diopside Ca(Mg,Al)(Si,Al) 2 O 6. a1) the liquid ceramic mass consisting of, in weight %, 50 - 75% of the ceramic material which is a mixture with particle-size distribution comprising minimum 90% of particles of size less than 0.04 mm, and the following phase composition: 30 - 90% of forsterite Mg 2 SiO 4, 5 - 15% of fayalite Fe 2 SiO 4 and 5 - 65% of a mixture of phase components such as chrysolite 2(Mg 0.88 Fe 0.12)SiO 2, enstatite MgSiO 3, tremolite Ca 2 Mg 5 Si 8 O 22 2, ringwoodite (Mg,Fe) 2 [SiO 4] and diopside Ca(Mg,Al)(Si,Al) 2 O 6, and a2) 25 - 50% of a binder comprising an aqueous or aqueous-organic colloidal solution of a metallic oxide and modifiers, and b1) the ceramic material for sprinkling which is a mixture having the following phase composition, in weight %: 30 - 90% of forsterite Mg 2 SiO 4, 5 - 15% of fayalite Fe 2 SiO 4, and 5 - 65% of a mixture of phase components such as chrysolite 2(Mg 0.88 Fe 0.12)SiO 2, enstatite MgSiO 3, tremolite Ca 2 Mg 5 Si 8 O 22 2, ringwoodite (Mg,Fe) 2 [SiO 4] and diopside Ca(Mg,Al)(Si,Al) 2 O 6.