SiAlON ceramics are used as ceramic cutting tools for heat-resistant super alloys (HRSAs) due to their excellent fracture toughness and thermal properties. They are manufactured from nitride and oxide raw materials. Mixtures of nitrides and oxides are densified via liquid phase sintering by using gas pressure sintering. Rare earth oxides, when used as sintering additives, affect the color and mechanical properties of SiAlON. Moreover, these sintering additives influence the cutting performance. In this study, we have prepared Yb_m/3Si_12-(m+n)Al_m+nO_nN_16-n (m = 0.5; n = 0.5, 1.0) ceramics and manufactured SiAlON ceramics, which resulted in different colors. In addition, the characteristics of the sintered SiAlON ceramics such as fracture toughness and microstructure have been investigated and results of the cutting test have been analyzed.