Needle-like fluorapatite and leucite containing glass-ceramic was prepared in a glass from the system SiO2 -Al2O3 - Na2O - K2O - CaO - P2O5 - CeO2 - F using high heating rates and crystallization temperatures between 700 - 1500 degrees C for dental restoration. Phase separation followed by both volume and surface crystallization of apatite and leucite respectively [1] were found after a two-step heat treatment of the powdered glass samples. Crystallization is demonstrated by X-ray diffraction patterns and electron micrographs. CIELAB colour differences (E*ab) and CIE 1976 lightness differences (L*) [4] were calculated utilizing rectangular coordinates (L*, a*, b*) measured by tristimulus colorometer in function of heat treating temperature. Results indicate that both colour and lightness differences decrease down to a scarcely shade of difference in temperature range of 1000 degrees C - 1150 degrees C.
