Abstract: The present invention discloses novel magnesia-spinel refractory compositions and bricks formed thereof that exhibit longer lining life, greater hot strength and reduced tendency to spall under high thermal loading conditions. The invention is designed to slow or retard the reaction between spinel and lime through the addition of zirconia in the form of an alumina-zirconia grain to the refractory mix. Zirconia reacts more readily with the lime in the refractory composition and surrounding environment to form calcium zirconate.