During grinding operations successively 'finer' grinding tools and conditions are employed. Fine grinding serves to improve the surface finish of workpieces but is generally not capable of easily removing the larger volumes of material required initially. Thus, there is a well recognized link between surface finish and the ease of material removal. In this paper we examine this relationship in a quantitative fashion for some optical materials for which a suitable data base is available. Grindability is considered in terms of the volumetric removal obtainable as a function of the applied normal load. For single crystal sapphire ground with a wide range of tools/conditions, this grindability measure is found to correlate approximately with the cube of the workpiece roughness. Similar correlations between grindability and finish are also found in comparing data for different glasses/crystals ground under identical conditions. The origins of this behavior are discussed in terms of possible micromechanical and dimensional explanations. Finally, since ease of material removal and workpiece finish are related, normalization against the roughness is proposed as a means for making comparison between different grinding media/conditions.