The sillimanite minerals: Andalusite, kyanite, and sillimanite

Abstract

The chemistry and the mineralogy of the three Al2O 3·SiO2 sillimanite minerals (anadlusite, kyanite, and sillimanite) are described. Their P-T diagram is discussed. The structural differences among the three are reviewed, emphasizing the coordination of the Al3+ cations that link the double octahedral chains within the structures. Their decompositions to produce mullite and silica are described and contrasted. The effect of nanomilling on those decompositions is discussed. Finally, the locations of commercial deposits and the industrial applications are addressed. © 2008 Springer-Verlag US.