Hello PIGs: Under the banner "Essays on the Study of Pegmatites", essay #6 is now posted: Jahns (1955): The Study of Pegmatites, with References to Bowen (1928, 1933) Jahns (1955) was a pivotal publication that established Jahns' authority in the study of pegmatites. If you read it, or at least my review of it, you will see that it was a radical departure from his first academic publication, Jahns 1953a (see Essay #5) of just a couple years earlier. As far as I have been able to discover, Jahns (1955) was the last time that Jahns (1953a) was cited by the author. David London Learn about pegmatites and join the Pegmatite Interest Group at http://www.minsocam.org/msa/Special/Pig/