Addition of different amount of zirconia (ZrO2) nucleating agent into MgO-CaO-SiO2 system to enhance the quality factor (Q x f) of CaMgSi2O6 diopside glass-ceramic for low sintering temperature process (from 850 to 950 degrees C) was carried out in this work. The microstructures, microwave dielectric properties and nucleating/growth mechanism of m-ZrO2 added CaMgSi2O6 system were analyzed using transmission electron microscopy (TEM) and electrical property measurements. Experimental results demonstrate that a solid solution of an amorphous phase MgO-CaO-SiO2 and ZrO2 forms after melted at 1500 degrees C. The t-ZrO2 appears in the amorphous matrix first and then crystalline CaMgSi2O6 particle grows up at around the boundary of t-ZrO2 after thermal treatment at 850 degrees C due to heterogeneous nucleating. Formation of t-ZrO2 is attributed to diffusion of Ca2+ to stabilize the m-ZrO2. The quality factor of CaMgSi2O6 was significantly enhanced by adding 3 wt.% m-ZrO2, indicating that the ZrO2 nucleating agent could enhance crystallization and therefore increase the quality factor. (C) 2012 Elsevier Ltd. All rights reserved.