SEM image courtesy of MA Galliski and J Cempírek (see Galliski et al., 2012)
Rossmanite was found in the Virorco dumortierite-bearing pegmatite
dikes in the Eastern Pampean Ranges of central Argentina (Galliski et
al, 2012). It generally consists of sub-millimeter portions of
rossmanite crystals in contact with schorl or elbaite. There is
evidence of fluid exchange between the host rock and the pegmatite
dikes that caused the primary elbaite-rossmanite to be partially replaced by
iron-rich tourmaline. Some crystals contain multiple species of tourmaline such as rossmanite, schorl and dravite.
(0.51Na0.44Ca0.05) (Al1.78Mn0.29Li0.78Fe0.12Zn0.02) Al6 (BO3)3 [Si5.44Al0.54O18] [(OH)3.0 F0.04] [(OH)0.96F0.04)]
Galliski MÁ, Mírquez-Zavalía MF, Lira R, Cempírek J, koda R (2012) Mineralogy and orgin of the dumortierite-bearing pegmatites of Virorco, San Luis, Argentina. Canadian Mineralogist 50, 873-894.