Fifty Minerals that Changed the Course of History is a fascinating compendium of the metals, rocks, organic minerals, and gems that have had the greatest impact on the development of human civilization from prehistory to the present day. Entries range from gold – the king of metals and the untarnished symbol of wealth, immortality, and power – to salt, the daily staple that is found in every kitchen and on every dining table, which, at one time, was literally worth its weight in gold. Arranged in chronological order of first use, the entries are judged by their influence in four categories: Commercial, Practical, Cultural and Scientific.