The invention relates to a fired refractory molded ceramic element that has the following characteristics: a) an MgO content of more than 62 percent by weight; b) a total CaO and SiO<SUB>2</SUB> content of less than 15 percent by weight, c1) the ratio CaO/SiO<SUB>2</SUB> being less than 0.27; and c2) a mixed forsterite crystal [(Mg,Ca)<SUB>2</SUB>SiO<SUB>4</SUB>] is provided as a siliceous secondary phase.
