Hydrogarnet; multi-site hydrogen occupancy in the garnet structure

Abstract

Hydrogarnet from low-gxade metamorphic rocks in the Quebec Appalachian5 has a relatively large unit-cell (approfmately 12.2 A) and low index of refraction (approximately 1.786). Fe-Mn zoning is common in these gains. Calculated formulae do not agee witl tle hydrogarnet formula, in which H4O4 substitutes for SiOa tebahedra, but require the presence of hydroxyl groups in another position in the structure.