Description
Lamprophyllite (named for its lustrous cleavage) is a rare but widespread Ti-silicate mineral commonly found in intrusive agpasitic igneous rocks. Yellow, reddish brow, vitreous, pearly white. There is a completely isomorphous range between lamprophyllite and baritoylpropyllite. Lamprophyllite is monoclinic; the mineral also has an orthorhombic polytype. Unit cell parameters depend primarily on the cationic composition at the A interlayer position [5]. The crystal structures of lamprophyllite-related minerals are based on HOH modules consisting of a central octahedral O-sheet sandwiched between two heteropolyhedral H-sheets. Lamprophyllite melts incongruently (880 °C) with the formation of titanium oxides: rutile, tausonite, Freudenbergite. Synthetic lamprophyllite synthesis has been crystallized from the melt. Tewly formed lamprophyllite shows a higher Sr/Ba ratio than in equilibrium melt
