gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1996.060.401.10 Mineralogy A Natural Ferrous Substituted Saléite from Arcu Su Linnarbu, Capoterra, Cagliari, Sardinia Vochten R. Van Springel K. Laboratorium voor chemische en fysische mineralogie, Departement Scheikunde, Universiteit Antwerpen, Middelheimlaan 1, 2020 Antwerpen, Belgium 8 1996 60 401 647 651 9 5 1995 24 7 1995 Copyright © 1996, The Mineralogical Society 1996 Abstract

Ferrous substituted saléeite is a new variety of saléeite from Arcu su Linnarbu, Sardinia. It is tetragonal with a = 6.982(2) c = 19.660(2) Å, Z = 2; the ideal formula is (Mg,Fe2+)(UO2)2(PO4)2·4H2O. The strongest lines in the X-ray powder diffraction pattern are: 3.473(100)(114), 4.95(50)(110), 4.91(40)(004), 4.443(40)(112), 2.200(30)(118), 2.193(30)(303) and 2.178(30)(009). The mineral is light-yellow in colour and is dull fluorescent. The measured density is 3.242 g/cm3 and Z = 2. There is a prominent (001) cleavage. Refractive indices are : α = 1.572(2) β = 1.577(2) γ = 1.581(2) and 2V = 48°(2). The pleochroism is very weak and the elongation is positive parallel to Y. The mineral occurs as subparallel crystal aggregates with a quadratic outline.

 Keywords saléeite ferrous substitution uranyl phosphate group Arcu Su Linnarbu Sardinia