Currently, diopside (MgCaSi2O6) crystal glaze is used frequently for pottery works or in earthen wares, though the process is not straightforward. However, to create and control the positions and sizes of the crystals in desired amounts when making pottery is difficult. To solve this problem, a diopside crystal seed was created at a temperature of 1450 oC. After planting this seed in the glaze, a glaze combination and firing process which allows a user to create crystals with the desired position and at the desired size were established. In addition, in order to investigate the creation process of the crystals, the growth patterns of the crystals were observed and examined using Raman spectrography and XRD and SEM analyses. As a result, the optimum synthesis condition of the diopside seed was created by mixing 1 mole of CaCo3, 0.2 mole of (MgCo3)4(MgCoH)2·5H2O and 2 moles of SiO2 and then applying a firing process to the mixture at 1,450 oC for 30 minutes. The optimum glaze content of the seed was 70 % feldspar, 20 % limestone and 10 % MgCo3. For the firing process, it was confirmed that the size of crystal is larger with a longer firing time at 1100 oC by completing a two-hour process at 1280 oC. In addition, the diopside crystal has columnar structure and is less than 1 μm in size.