As nodules in cavities intergrown with grattarolaite. Isostructural with berlinite; polymorphic relationship with heterosite.
Approved IMA 1997 (Dana # Added)
The Castelnuovo mine, Santa Barbara lignite area, Upper Arno River Valley, 30 km SE of Florence, Italy. Link to MinDat.org Location Data.
Named after Francesco Rodolico (1905�1988), professor of mineralogy, University of Florence, Italy, specialist of the history of geology and of building and ornamental materials, au thor of Le pietre delle citt� d�Italia