Eur. J. Mineral. 2018, 30, 621–634 Minerals and materials: Published online 27 April 2018 building principles and applications Crystal chemistry of schoonerite-group minerals 1,* 2 3 1 IAN EDWARD GREY ,ANTHONY R. KAMPF ,ERICH KECK ,COLIN M. MACRAE , 4 5 JOHN D. CASHION and YESIM GOZUKARA 1 CSIRO Mineral Resources, Private Bag10, Clayton, Victoria, 3169, Australia *Corresponding author, e-mail:
[email protected] 2 Mineral Sciences department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 900007, USA 3 Algunderweg 3, 92694 Etzenricht, Germany 4 Monash University, School of Physics and Astronomy, Victoria 3800, Australia 5 CSIRO Manufacturing, Private Bag 10, Clayton South, Victoria 3169, Australia Abstract: Synchrotron single-crystal structure refinements for five schoonerite-group minerals (SGMs) from the Hagendorf Süd, Bavaria, and Palermo No.1, New Hampshire, pegmatites were combined with results from previous studies on type schoonerite and the SGMs wilhelmgümbelite and schmidite to evaluate the main crystallochemical relations between the minerals. Elements Zn and Fe3þ are essential to the structure and are ordered in specific sites, while Mn and Fe are distributed relatively uniformly over three octahedral sites, M1, M2andM3. The Mn/(Mn þ Fe) atomic ratio is relatively constant for the samples studied, ∼0.26–0.31, and is close to this ratio in the primary phosphate, triphylite, from which the SGMs are derived. The main crystallochemical variations are due to different degrees of oxidation of the Fe, which ranges from 45% of the total Fe as Fe3þ in green SGMs, to 98% of the Fe as Fe3þ in red SGMs.