Topaz, Al₂SiO₄(F,OH)₂, belongs to which listed mineral class?

Explanation

Topaz is an aluminium silicate containing fluorine and hydroxyl groups, commonly written Al₂SiO₄(F,OH)₂. Its classification is therefore silicate. Fluorine and hydroxyl can substitute in the mineral structure, so the combined expression should not be read as a single FOH ion.