The Bond method of grindability was applied to ceramic raw materials (quartz, kaolin and feldspar) and to their binary and ternary mixtures. The Bond work indices of the admixtures containing a softer component (kaolin) were found to be greater than the weighted average of the work indices of the individual components in the mixture. As a result, separate grinding of ceramic raw materials seems to require less specific energy input than grinding them in admixtures. (c) 2005 Elsevier Ltd. All rights reserved.