OPTICAL PROPERTIES AND CRYSTAL STRUCTURE OF TRICLINIC GROWTH SECTORS IN VESUVIANITE

Abstract

Sectored vesuvianite showing optically triclinic properties was studied by X-ray and P-FTIR analyses, and the origins of the internal optical texture are discussed. A monoclinic refinement (space group P2/n) suggests that site occupancies are slightly different among the AI(2) series, though the OH-dipole is randomly oriented in all sectors. A relationship between the surface and internal texture suggests that these sectoral structures were produced during crystal growth, not by phase transitions.