This species, a hydrous zinc phosphate, Zn3P2O8.4H2O, dimorphous with hopeite, was first described by Spencer in 1907. While the material then available was suitable for the physical and chemical description of the new mineral, it did not permit a full crystallographic investigation. Spencer noted that the crystals resembled in a general way those of hemimorphite, and made sufficient measurements to indicate the triclinic character of the mineral. In his sketch of a crystal he indicates that the mineral is twinned, and that this twinning is best seen on the perfect cleavage which is parallel to the brachypinacoid.