Paulkellerite, a new bismuth iron phosphate mineral from Schneeberg, Germany

Paulkellerite [Bi (sub 2) Fe (super 3+) (PO (sub 4) )O (sub 2) (OH) (sub 2) , monoclinic, C2/c, a 11.382(6), b 6.690(4), c 9.666(6) Angstrom, betassociated with native bismuth, a skutterudite-group mineral, pyrite, erythrite and bismutoferrite at the Neuhilfe mine, Schneeberg, East Germany. Optically biaxial, 2V (sub gamma) 37(2) degrees , with alpha 1.762(2), beta 1.767(2), gamma 1.825(5), paulkellerite is light greenish yellow and without cleavage. The strongest powder XRD lines are 3.123(10), 2.162(4), 2.804(3), 1.442(3) Angstrom. The name honours Professor Dr. Paul Keller of the University of Stuttgart.