The rapid growth of gemological sciences and mineralogy requires a comprehensive dictionary for gemologists, mineralogists, geologists, jewel dealers, industry, and hobbyists. The third edition of this dictionary contains about 24,000 entries – about 4,000 more than the second edition. The comprehensive definitions are now completed by more than 1,500 charts, diagrams and figures. The author offers a one-stop reference to any matter dealing with gems and gemology.