Rossmanite rarely occurs in the pegmatite along with elbaite and fluor-elbaite.
Composition:
The compositions of an ndividual analysis in the rossmanite field is indicated by the following diagram:
Reference:
Dixon A, Cempírek J, Groat LA (2014) Mineralogy and geochemistry of pegmatites on Mount Begbie, British Columbia. The Canadian Mineralogist 52, 129-164.