Princivalleite, Na(Mn<sub>2</sub>Al)Al<sub>6</sub>(Si<sub>6</sub>O<sub>18</sub>)(BO<sub>3</sub>)<sub>3</sub>(OH)<sub>3</sub>O, a new mineral species of the tourmaline supergroup from Veddasca Valley, Varese, Italy
Mineralogical magazine