It is one of the rare phosphate minerals that comes from classic mineral localities such as Hagendorf, Germany and the Palermo Mine in New Hampshire. It is closely related to the mineral laueite . But a closer inspection reveals the only difference being two more water molecules in laueite's formula. Those two water molecules make a difference in the structure and a difference in the crystal habit of the two minerals. Laueite forms tabular crystals in contrast to strunzite's acicular or hair-like crystals.
Color is bright straw yellow to brown-yellow or brown.
Luster is vitreous to silky. Specimens are translucent to transparent. Crystal Habits include acicular to fibrous crystals in radiating sprays and in fibrous crusts. Cleavage is absent. Fracture is uneven.