Gem Characterisation

The purpose of this Special Issue is to present the advances in gem characterisation using principally non-destructive means. The proper identification of gems is an ever-increasing challenge, especially with harder-to-detect treatments and the new demands on geographical origin determination. In order to grow, gemmology requires valuable inputs from other fields of science, as well as more fundamental studies concerning gems. Hopefully, this series of articles will contribute to a better understanding of the characteristics of some gems.