The pure Sr(2)Y(8)(SiO(4))(6)O(2) oxyapatite powder materials have been ball milled and spark-plasma sintered. The microstructures and transmittances in the completely and incompletely densified ceramics were investigated. The ceramic sintered at 1500 degrees C is translucent with 0.7% porosity and its total forward light transmittance can reach about 52% in the infrared region. The transmittance was interpreted based on the microstructures of the ceramic samples and the Mie scattering theory.