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An Overview Of Tourmaline Mineralogy From Gem Tourmaline Producing Pegmatite Districts In Africa, Brian Giller

University of New Orleans Theses and Dissertations

Suites of gem-quality faceted tourmaline, slices and fragments from Nigeria Namibia, Mali, Tanzania, Congo and Mozambique were quantitatively analyzed to determine mineralogy and minor elementChemistry. The specimens range in color from colorless to pink, red, yellowish-brown, green, bluish-gray, blue, brown and black. The results show that these tourmalines are elbaite, liddicoatite, rossmanite and schorl. Fe, Mn and Ti are the principal chromophores of the studied tourmaline. Fe is the most dominant and causes green, blue, dark-brown and black colors. Mn imparts pink and red hues. Correlations between Mn content and pink color intensity were not found. The Mn2+¡êTi4+ charge transfer …