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Pegmatites are sources of gem-quality crystals of beryl, tourmaline, topaz, spodumene, and spessartine. Historic localities are found in Brazil, Madagascar, Russia, and the United States, but important deposits have recently been discovered in Africa and Asia. Most high-quality gem minerals occur in miarolitic cavities found near the centers of pegmatite bodies or in reaction zones between pegmatites and ultramafic host rocks. The most important gem-bearing granitic pegmatites formed at shallow levels in the continental crust during the latest stages of collisional plate tectonic events. Single, spectacular miarolitic cavities in some pegmatites have produced tons of gem crystals valued in excess of $50 million.

With their multitude of colors, gem tourmalines are among the most popular colored gemstones. Spectacular color-zoned tourmalines are valued as gems and crystal specimens, and some complexly zoned crystals contain nearly the entire spectrum of color variation found in the mineral world. The top-quality “neon” blue-to-green, copper-bearing tourmaline, the Paraiba-type , is one of the highest-priced colored gemstones, with values comparable to those of some diamonds. The wide variety and intensity of colors are related primarily to color-producing ions in the structure and to exposure to natural radiation. Gem tourmalines that form in magmatic, pegmatitic environments are most commonly elbaite and fluor-liddicoatite species, and the rarer gem tourmalines that develop in metamorphic rocks are generally dravite–uvite species.