Minerals must have a natural origin in order to be minerals. However, these minerals were only indirectly affected and the study of their origins is best left to mineralogists. Fiedlerite and others minerals with similar chemistries belong to a division in the Halide Class called the Oxyhalides and Hydroxyhalides . These minerals have either oxygen or hydroxide groups in their chemistries. The oxygen atom in their chemistries might require their classification in the Oxides Class of minerals except that their structures are more tied to the halide elements and the oxygens and hydroxides are kind of superfluous to the overall structure.
Color is colorless and white.
Luster is adamantine. Crystals are transparent to translucent. Crystal Habits include tiny tabular to platy crystals. Cleavage is good, but not discernible. Fracture is conchoidal.