Jarosite is isostructural with natrojarosite which means that they have the same crystal structure but different chemistries. The two minerals are difficult to distinguish without a chemical test. The symmetry of jarosite is the same as the members of the Tourmaline Group . Crystals of jarosite however do not form prismatic crystals like those of the typical tourmaline mineral. Jarosite's crystals are more flattened and resemble nearly cubic rhombohedrons.
Color is an amber yellow or brown.
Luster is vitreous to resinous. Crystals are transparent to translucent. Crystals are somewhat scarce and small, more commonly as earthy masses, films or crusts, botryoidal and granular. Cleavage is good in one direction but only seen in the larger crystals. Fracture is uneven.