The Hamaker constants of 8 different ceramic materials, 6H-SiC, tetragonal, partially stabilized-ZrO2 (3% Y2O3), b-Si3N4, a-Al2O3, Y2O3, sapphire (single crystal a-Al2O3), MgO, MgAl2O4, and fused silica, across air, water, and n-dodecane at room temperature and across silica at 2000 K have been calculated from optical data using Lifshitz theory. Spectroscopic ellipsometry was used to measure the photon energy dependence of the refractive index, n, and the extinction coefficient, k, in the visible and near-UV range on several important ceramic materials. This relatively simple, nondestructive technique has proved to yield reliable optical data on sintered, polycrystalline materials like Si3N4, SiC, ZrO2 and Al2O3. For the other materials, Y2O3, sapphire, MgO, MgAl2O4 and fused silica, optical data from the literature were used to calculate the Hamaker constants. The calculated Hamaker constants were estimated to be accurate within ± 10%.