Natural rock-forming minerals and many synthetic materials have traditionally been characterized by electron microprobe analysis (EMPA). However, recent advances in technology have created attractive alternatives to EMPA that focus instead on bulk chemistry and high-resolution surface studies. The purpose of this abstract is to demonstrate the continued usefulness of careful electron microprobe analysis as part of a well-coordinated analytical study. To this end, a brief summary is presented of the role the electron microprobe played in the recent discovery of yoshiokaite, a new Ca, Al-silicate mineral and one of only three new minerals discovered on the Moon.[l]

Regolith breccias returned by several Apollo missions were subjected to extensive bulk chemical studies at the University of California, Los A n geles.[2] These bulk chemical studies focused particularly on key trace elements that might identify exotic regolith breccias.