Mechanical strength of 20%, 30% and 40% at 900 °C, 1000 °C and 1100 °C tested was in the range of 31–53 MPa (Fig. 9), which is within the range required by ISO 13006 for the manufacture of ceramic tiles. The strength results increased with increasing firing temperature whereas decreased with increasing rock dust percentage. Young's modulus, like other elastic properties, is a function of the sample dimensions and density. Results of Young's modulus of the samples also increased with increasing temperature, the mechanical strength has the same type of behavior during firing as the modulus. For 20% and 30% mixing of rock dust mechanical strength as well as Young's modulus significantly improved from 900 °C to 1100 °C.