Uniform zinc sulfide spheres and multimers ranging in size from ∼ 90 nm to 1.0 micron were produced in large quantities by adding varying amount of supernatant in a secondary nucleation process. The particle morphology was investigated using scanning and transmission electron microscopy. Smaller particles exhibited increased surface roughness in the nitrate system. Characterization by x-ray and electron diffraction showed that the particles were built up from nanocrystallites. The relationship between the particle size, porosity, and refractive index was studied by modeling UV-Vis spectra using the Mie scattering method. Monodispersed zinc sulfide spheres and multimers in the size range from 100 nm to 600 nm can be used as high refractive index building blocks for photonic crystals with band gaps covering the entire visible spectrum as well as portions of the near-IR and UV regions.