The rapid growth of gemological sciences and mineralogy requires a comprehensive dictionary for gemologists, mineralogists, geologists, jewel dealers, industry, and hobbyists. The second edition of this dictionary contains about 25,000 entries a" about 9,000 more than the first 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.