It is closely related to its cousin, tsumebite . The two minerals are in a series in which the arsenate ion group in arsentsumebite is replaced by a phosphate ion group in tsumebite. Both are formed in the oxidation zone of lead-copper ore deposits. Both minerals are unusual in that they have two ion groups instead of the usual one in most minerals. It the case of arsentsumebite, it has an arsenate ion group and a sulfate ion group.
Color is green.
Luster is vitreous. Transparency crystals are transparent to translucent. Crystal System is monoclinic. Crystal Habits include tabular crystals that can form twinned trillings and also as crusts. Streak is green.