A ceramic block consisting essentially of substantially homogeneous (Y2O3)χ P2O5, where 0.95≦x≦1.05, having length LL, a width WW and a height HH, and a volume W of at least 8×10−3 m3 essentially free of cracks throughout the volume, a density of at least 85% of the theoretical maximal density of Y203.P2O5 under standard conditions, and a creep rate CR at 1250° C. and 6.89 MPa; where CR≦8.0×10−6 hour−1 and method for making the same. The method utilizes a dry process where the starting YP04-based ceramic material is synthesized by reacting anhydrous P2O5 with dry Y2O3 powder.