Crystal chemistry of titanite-structured compounds: the CaTi1-xZrxOSiO4 (x≤0.5) series

Abstract  Inhomogeneous aggregates of late-stage titanite enriched in Zr have been described recently from post-magmatic parageneses in silica-undersaturated rocks. In the natural samples, simple isovalent substitution of the large Zr ([vi]R4+=0