AM_Geigerite Formula: As4 Mn5 O26 H22 Name: Geigerite Unit cell: 7.944 10.691 6.77 80.97 84.2 81.85 , V=560.28 Space group: P-1 (2)

Graeser S , Schwander H , Bianchi R , Pilati T , Gramaccioli C M , American Mineralogist , 74 (1989) p.676-684, Geigerite, the Mn analogue of chudobaite: Its description and crystal structure