Excerpt from Gems: Notes and Extracts Minerals consist of all those substances which have neither animal nor vegetable life, and are therefore devoid of sensation, existing merely by the power of aggregation or chemical affinity. The science which treats of minerals is called Mineralogy, and is divided into two distinct branches, viz., that which preserves the name, and treats simply of minerals with regard to their component elements, and Geology, which regards minerals pure or mixed, as they exist in nature and in relation to the soil. Mineralogy describes the individual quality of the various mineralogical species; geology treats only of minerals as constituent parts of the earth. Those minerals which are used ornamentally and are prized for their rarity are called Gems. In mineralogy, as in other departments of natural history, minerals are united in groups, forming great classes, which are divided into genera, species, and varieties. 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.