The phosphate anion group would normally dictate that hinsdalite be classified in the Phosphate Class of minerals. But hinsdalite's sulfate anion is intricate and essential in its structure, while the phosphate anions can be substituted for to at least a limited degree, by other anion groups. Some other classification schemes may place hinsdalite in the Phosphate Class however. Color is yellow, golden-yellow, greenish yellow, green to colorless. Luster is vitreous to greasy.
Specimens are mostly translucent to small crystals being transparent.
Crystal System is trigonal. Crystal Habits include pseudocubic and pseudotetragonal rhombohedrons and modified rhombohedrons. Clusters of spherical flakes and tablets are known. Faces tend to be curved and striated. Granular or massive formations are also seen.