Some of the published analyses of specimens of Dufrenite have afforded results not in good accord with the chemical formula 2Fe2O3, P2O5, 3H2O, usually ascribed to that species.

Moreover, since analyses of a crystallised Dufrenite from Cornwall gave results showing a higher ratio of acid to base than demanded by the above formula, a re-examination of the ordinary botryoidal variety of the mineral seemed desirable.