Forsterite (Mg2SiO4) ceramics were prepared using Mg(OH)(2) and SiO2 as precursors, and the effect of powder characteristics of Mg(OH)(2) on calcination and sintering was investigated. The use of highly dispersed Mg(OH)(2) powder (HD powder) resulted in a lower calcination temperature. Forsterite powder of high homogeneity and small particle size prepared from the HD powder enabled synthesis of high-density forsterite ceramics by ordinary sintering without applying external pressure. Moreover, transparent forsterite ceramics were successfully synthesized through addition of excess Mg to the precursors to compensate for Mg evaporated during the sintering process. Subsequent dielectric measurements revealed that the transparent forsterite ceramics had a very low dielectric loss (tan delta < 10(-4)).