Book excerpt: This book provides a lucid introduction to the basics of gemmology. It familiarizes archaeologists, art historians and conservators with the science of gemstones and allows them to understand the basic concepts of their provenance, typology and treatments. Which are the main types of gems? What treatments can be applied? How does one analyse gems? How can gems contribute to archaeometrical research? This volume is written by four experts in the fields of gemmology and archaeometry and addresses both students who need an introduction to this field and professionals who want to refresh their knowledge of the topic. This work is part of a series of introductory texts that deal with a broad range of materials-related topics in archaeometry.