AM_Talmessite Formula: Ca2 (Mg.65 Co.35) As2 O10 H4 Name: Talmessite Unit cell: 5.874 6.943 5.537 97.3 108.7 108.1 , V=196.76 Space group: P-1 (2)

Catti M , Ferraris G , Ivaldi G , Bulletin de Mineralogie , 100 (1977) p.230-236, Hydrogen bonding in the crystalline state. Structure of talmessite,, Ca2(Mg,Co)(AsO4)2*2H2O, and crystal chemistry of related minerals, Locality: Bou-Azzer, Morocco