...Jakub Plášil; Karla Fejfarová; Jiří Čejka; Michal Dušek; Radek Škoda; Jiří Sejkora Abstract The previously published crystal structure study suggested that haiweeite is orthorhombic, Cmcm , with a = 7.125(1), b = 17.937(2), c = 18.342(2) Å, and V = 2344.3(7) Å 3 , and an ideal chemical formula Ca...

...Peter C. Burns Abstract The structure of haiweeite, Ca[(UO 2 ) 2 Si 5 O 12 (OH) 2 ](H 2 O) 3 , Z = 4, orthorhombic, a 7.125(1), b 17.937(2), c 18.342(2) Å, V 2344.3(7) Å 3 , space group Cmcm , has been solved by direct methods and refined by full-matrix least-squares techniques to an agreement...

...William G. R. de Camargo; Darcy P. Svisero Abstract Haiweeite has been found at Perus, San Paulo, Brazil, along fractures of a tourmaline-bearing granite. The needle-like crystals of monoclinic symmetry have the optical constants: α = 1.533, β = 1.572, γ = 1.573; 2 V x = 18°; pleochroism pale...

...T. C. McBurney; Joseph Murdoch Abstract A hydrous calcium uranium silicate, found near the Haiwee Reservoir in the Coso Mountains, California, has been determined as a new mineral and named haiweeite, from the locality. It occurs as spherulitic aggregates, or single flake-like grains, on fracture...

... to coffinite, followed by minor fibrous coffinite forming in veins. Uranyl minerals, mostly uranophane with minor haiweeite precipitating in veins and in hand sample-scaled breccias, are present in significant amounts ( ca . 5% of the ore) not observed elsewhere in the Athabasca Basin. The multi-stage...

.../Th ratio in mineralized leucogranite is 541ppm, 147 ppm and 2.85, respectively. Main ore mineral is uraninite and its altered form - gummite, while secondary uranium minerals such as schoepite, uranophane and haiweeite are also identified in leucogranite by XRD. Reconnoitory drilling of ten boreholes...

... with a U:Si ratio of 1:1. Haiweeite, Ca[(UO 2 ) 2 Si 5 O 12 (OH) 2 ](H 2 O) 3 , and weeksite have U:Si ratios of 2:5, and their structures are substantially different from that of other uranyl silicates ( Burns et al. 1996 , Burns 2001 ). Uranyl silicates are likely to be abundant in a geological...

... the composition [ ( UO 2 ) ( Si O 4 ) ] n − 2 n and are crosslinked by a bridging oxygen atom to form a uranyl silicate sheet. These sheets are crossbonded by the additional cations in the structure. The uranyl minerals with a uranium to silicon ratio of 1:3 include week-site and haiweeite. A partial structure...

... metaschoepite . American Mineralogist , 92 , 662 – 669 . McBurney T.C. Murdoch J. ( 1959 ) Haiweeite, a new uranium mineral from California . American Mineralogist , 44 , 839 – 843 . Merlet C. ( 1994 ) An accurate computer correction program for quantitative electron-probe...

...F igure 6. EXAFS (left) and FT (right) spectra for ( a ) haiweeite and ( b ) soddyite. Solid lines represent experimental data; dashed lines represent fits. ...