...-tantalum (LCT) family P-rich Buranga granitic pegmatite (western Rwanda) is used as a type locality to address this question. NTO mineralization in the Buranga dike occurs in two mineralogical units: in mineralogically complex phosphatic nodules, and in albitized parts. In the phosphatic nodules, Fe-Nb-Ta...

... symmetry C2/c both at room temperature and at 100 K. At room temperature the lattice parameters are a = 11.9721(9) Å, b = 12.5988(8) Å, c = 6.5029(5) Å, β = 114.841(8)° with Z = 4. For reasons of comparison the structure of an alluaudite sensu strictu (s.s.) from Buranga (Rwanda) was re-determined...

...Frédéric Hatert; Pierre Lefèvre; André-Mathieu Fransolet Abstract A sample of bertossaite {CaLi 2 [Al 4 (PO 4 ) 4 (OH,F) 4 ]} from the Buranga pegmatite, Rwanda, was investigated by single-crystal X-ray diffraction, electron microprobe, and infrared spectroscopic techniques. Under the polarizing...

...Fig. 3. Infrared spectrum of ferrorosemaryite from Rubindi (A), compared to that of alluaudite from Buranga, Rwanda (B). ...

...Frédéric Hatert; Miguel Galliski; Encarnación Roda-Robles; Pietro Vignola; André-Mathieu Fransolet Abstract Three samples of minerals belonging to the wyllieite mineral group were structurally investigated: wyllieite from the Buranga pegmatite, Rwanda (A); wyllieite from the Malpensata pegmatite...

...Andre-Mathieu Fransolet; Francois Fontan; Paul Keller; Diano Antenucci Abstract New results of wet-chemical and electron-microprobe analyses are given for an occurrence of johnsomervilleite from the Kiluli pegmatite, Rwanda, and for samples of fillowite from the granitic pegmatite bodies of Buranga...

...Frédéric Hatert; Raphaël P. Hermann; André-Mathieu Fransolet; Gary J. Long; Fernande Grandjean Abstract Rosemaryite, ideally NaMnFe 3+ Al(PO 4 ) 3 , has been collected in the Buranga pegmatite, Rwanda. A single-crystal structure refinement was performed to R 1 = 4.01 %, in the P 2 1 / n space...

... ) The eosphorite – childrenite series associated with the Li-Fe-Mn phosphate minerals from the Buranga pegmatite, Rwanda . Mineralogical Magazine 43 , 1015 – 1023 . Fransolet A.-M. ( 1982 ) Minéralogie de Belgique. Ardennite . Bulletin de la Société belge de Géologie 91 , 50 . Fransolet...

... by Moore (1971) . Although a metasomatic origin seems to be valid in many cases ( Huvelin et al. 1972 ), caution has been expressed about the occurrence of alluaudite sensu stricto in the Buranga mine, Rwanda ( Fransolet 1977 , Héreng 1989 ). More recently, fillowite – alluaudite parageneses...

... investigated: (A) fillowite from the Buranga pegmatite, Rwanda; (B) fillowite from the Kabira pegmatite, Uganda; (C) johnsomervilleite from Loch Quoich, Scotland; (D) johnsomervilleite from the Malpensata pegmatite, Italy; and (E) chladniite from the Sapucaia pegmatite, Minas Gerais, Brazil. Their crystal...

.... The shaded M(1) octahedra are occupied by Mn, the unshaded M(2) octahedra by Fe. The large circles indicate Na on the A(1) site, and the small circles Li and Na on the A(2)’ site. The alluaudite crystal structure was first described by Moore (1971) for a natural sample from Buranga, Rwanda...

...Fig. 2. Polarized electronic absorption spectra of a heterosite crystal in 6 μm thick platelet of the heterosite-ferrisicklerite intergrowth from Buranga, Rwanda. The deeply violet heterosite and coexisting ferricsicklerate ( cf. Fig. 1c ) show nearly parallel extinction. ...