Gem Formation, Production, and Exploration: Why Gem Deposits Are Rare and What is Being Done to Find Them

The geology of gem deposits is a relatively new area of research focused on understanding the rare and exceptional geologic conditions that give rise to gem-quality materials. These conditions may include the availability of sometimes uncommon major constituents, the presence of adequate chromophores, limited concentrations of undesirable elements, open space, an environment conducive to forming crystals of sufficient size and transparency, and a favorable environment for mining. Future research should aid exploration, which until recently has been nonsystematic and nonexistent for many gem minerals, with diamond as the notable exception.