Excerpt from The Principles of Economic Geology Deposits that have been precipitated from aqueous solutions in and along fractures in rocks receive but scant attention in'the other branches Of geologic science as now developed, and the study Of such deposits is especially appropriate in the economic branch. Certain definitions, most of which refer to veins or to vein formation, are given below. The list is not exhaustive; the student is advised to refer to the index for other definitions that are introduced at appropriate places in the text. An ore is a mineral or association Of minerals that may, under favorable conditions, be worked commercially for the extraction of one or more metals. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.