The influence of small amount (1 or 2 wt%) of TiO2 additions and crystallization heat treatment on the elastic properties of a mica based glass ceramic have been investigated by ultrasonic velocity measurements. The mica based glass ceramic was prepared through controlled crystallization of a glass in the SiO2, Al2O3, CaO, MgO, K2O and F system. Evidences of TiO2 acting as a nucleating agent in this system was demonstrated. The longitudinal and transversal wave velocities of the as-prepared glass and the mica based glass ceramic were measured by using 5 MHz probes at room temperature. Elastic properties namely; longitudinal modulus, Young's modulus, bulk modulus, and shear modulus were calculated from the ultrasonic velocity values measured and density values obtained experimentally. It has been observed that small amount of TiO2 additions caused a notable but not significant; however, the crystallization heat treatment had a profound effect on the elastic properties of the glass in the system studied. (c) 2005 Elsevier B.V. All rights reserved.