Among the extremely valuable donations made to the museum of the Mining Institute, there is a specimen of false crystals of enormous size: currently composed mainly of malachite substance. From this specimen one could distinguish small tabular pseudomorphs that perfectly preserved their original shape, partly even with mirror-shiny edges . Thanks to this circumstance, the method of crystal chemical analysis could be applied with extreme clarity, so that it could be stated with complete certainty that these were pseudomorphs of atacamite. Using the tables of crystal chemical analysis, the entire series of substances was revised according to the symbol closest to that obtained from an approximate measurement, and the identity of the form turned out to be only for one substance, namely atacamite. These data are given in the note.
