“…Therefore, variations of aging time were carried out for 18 and 24 hours at a temperature of 800°C. In the XRD test in Figure 2(b) with a heating temperature of 800°C, the aging time of 18 and 24 hours shows that zircon contains silica with a cristobalite phase [15]. Based on the data JCPDS: 36-1451, the appearance of cristobalite-phase silica appears at the top of the graph with an angle of 21.89, 25.52, 28.36, 31.67, 36.01, 42.52, 46.78, 53.81, 56.39, 60.25, 64.89, and 72.99.…”