The relative colloidal stability in ethanol of ceramic powders with Si-O surface groups (Si3N4, SiC, and MoSi2) is reported. SiO2/EtOH suspensions are also examined as a reference. The comparative relationships between pH, particle-surface charge, zeta potential, stability, and suspension rheology are discussed. The nature and influence of the surface species are determined, and the similarities and differences are compared. DLVO theory was used to define suspension stability, and it was found that non-oxide particles in EtOH are charge-stabilized and have viscosity and flow curves that agree with the electrokinetic measurements.