Chemistry is familiar enough; fire and fermentation are cornerstones of human civilization, and the beaker and the test tube are readily recognizable icons in most of the world. Flow is even more familiar; everyone has seen a river, felt the wind, taken a pulse. Though they are rarely on the center stage, fluids that undergo chemical reactions as they flow also impact an astonishingly large number of human experiences. Examples of this include air purification, electro-chemical transport within the human brain, blood and air flow through lungs, flow through kidneys, catalytic converters, tooth decay, deterioration of historic objects, and nearly every large-scale manufacturing process, from semiconductors to paper. Besides the sheer number, the diversity of this list is impressive.

The authors of this volume presented a short course on the rare earth elements to about 80 participants in San Francisco, California, December 1-3, 1989, just prior to the fall meeting of the American Geophysical Union. This was the nineteenth in a series of short courses that the Mineralogical Society of America (MSA) began sponsoring in 1974. It was the brain-child of Robert Hazen and David Stewart, and the latter was the agent who recruited Bruce Lipin (and later, Gordon McKay) to undertake this monumental work. This book joins a long list of Reviews in Mineralogy (see opposite page for details) that MSA has made available to the scientific community at reasonable cost. The editors and authors thank Mrs. Marianne Stern and Mrs. Margie Sentelle at Virginia Tech for their tireless efforts (under considerable pressure) in preparation of camera-ready copy for this volume. We also thank Mr. Todd N. Solberg for helping with word-processing problems on the computer. <...>

Geochemistry is a frequently used term in geological studies that defines a discipline which has developed in importance over the past 40 years. The meaning of this term and the substance of the discipline is the relationship between the chemical properties of elements found in the geological sphere and their expression as minerals or other phases found in rocks. Essentially the elements that are the most common and abundant in surface materials are limited in number, such as Na, K, Mg, Ca, Al, Si, and Fe (called the major elements) with concentrations of elements such as Mn, P, S, C, Cl present in smaller amounts and considered as minor elements. The elements of industrial importance, such as the transition metals Cu, Cd, Co, Ni, Ti, and Au, among others, are of yet lesser abundance in rocks and most often occur as inclusions in phases dominated by major elements or as isolated concentrations due to special geological conditions. Other elements of low overall abundance in rocks such as As, Sb, and Sn are more difficult to classify in that their occurrence is limited to small and sporadic concentrations in rocks. In the classical geological chemical framework the elements found as gases in the atmosphere such as Ar, N, Ne, He, and others are little present. Some atmospheric elements such as C and O are present in both the realm of geological occurrence and the sphere of the surface atmosphere. Geochemistry is the study of the occurrence and reasons for these occurrences of different elements.

Geochemistry in Mineral Exploration is a pioneering text and reference book dealing with the newer phases of an ancient and important subject that has intrigued man ever since the days he began to use metals rather than stones for his weapons and implements.