Gem-Bearing-Pegmatites-A-Review.pdf

GEM-BEARING PEGmTITES : A REVIEW By lames E. Shigley and Anthony R, Kampf

Many of the important gem ~nineralsseen on today's marliet-aquamarine, tourmah e , and topaz, among others-come from an unzisual type of rock lznown as a pegmatite. Gem-bearing pegmatites are crystalline igneous rocks that are distinguished b y their large-size crystals, concentrations o f certain chemical elements otherwise rare i n the earth's crust, and various u r j u s ~ ~minerals. al l'egmatites are typically rather small bodies of roc)