Abstract
Third in the series of collaborative studies launched by the International Working Group “Analytical Standards of Minerals, Ores and Rocks” (IWG), the study on Ailsa Craig Granite AC‐E has attracted the participation of 128 laboratories from 29 countries. Tables of compiled data, 3212 results in all, are presented with working values, recommended or proposed, for seventy major, minor and trace elements. The success of this study which lasted for only one year from the distribution of sample to the release of the present report is to be attributed entirely to the record participation of the IWG‐Member laboratories.