Hureaulite, Mn +2 5 (H 2 O) 4 (PO 3 (OH)) 2 (PO 4 ) 2 , from different deposits of the Totoral pe... more Hureaulite, Mn +2 5 (H 2 O) 4 (PO 3 (OH)) 2 (PO 4 ) 2 , from different deposits of the Totoral pegmatitic field, San Luis. Hureaulite, a hydrated manganese (II) phosphate mineral, has been found in three different pegmatites of the Totoral pegmatitic field, San Luis ranges, Argentina. In Santa Ana mine, a berillium-bearing pegmatite located in the Cerro La Torre group, this phosphate mineral occurs associa- ted with eosphorite as little prismatic idiomorphic crystals implanted on sicklerite exfoliation surfaces, and originated by the hydrothermal altera- tion of primary lithiophilite. In Ranquel, a berillium-bearing pegmatite located in the Loma Alta group, hureaulite is associated with ferrisicklerite, purpurite, phosphosiderite, strengite, reddingite, meta-autunite, eosphorite, vivianite and hydroxil-apatite and has been formed by hydrothermal reworking of triphylite; the crystals are 5 mm in length and show typical monoclinic forms. In San Luis II, a lithium-bearing pegmatite loc...
espanolLa yacencia de cacoxenita, Fe3+24AlO6(PO4)17(OH)12•75H2O, ha sido determinada en la pegmat... more espanolLa yacencia de cacoxenita, Fe3+24AlO6(PO4)17(OH)12•75H2O, ha sido determinada en la pegmatita berilifera Ranquel, grupo Loma Alta, distrito pegmatitico Totoral, San Luis, Argentina. Este fosfato mineral ocurre como agregados esferuliticos amarillos a pardo amarillentos, con estructura interna en forma de rosetas, alojados entre cristales de vivianita o tapizando pequenas cavidades sobre otros fosfatos metasomaticos o hidrotermales. Opticamente, el mineral es uniaxico (+), con ω = 1,572 y e = 1,642; su pleocroismo es debil, con O = amarillo palido y E = pardo amarillento. Su difractograma de rayos X muestra como lineas mas intensas [dobs en A(I/I0)(hkl)]: 11,88(100)(200), 13,78(18)(110) y 6,83(12)(121, 211). Los parametros de celda son: a 27,531(8) A, c 10,549(1) A y V 6927(2) A3, con c/a 0.383. La composicion quimica, basada en analisis EDS y WDX, muestra P, O, Fe, Mn y Al. Cacoxenita ha cristalizado en un estadio hidrotermal tardio bajo condiciones de alta oxidacion EnglishC...
San Guillermo, Santa Amalia, Andacollo and El Chanar muscovite-bearing pegmatites from Balilla an... more San Guillermo, Santa Amalia, Andacollo and El Chanar muscovite-bearing pegmatites from Balilla and Aurora pegmatite groups, are located between 30o30´ and 30o47´S and 67o29´ and 67o43´W, in the Sierra de Valle Fertil, northwestern Argentina. The deposits are hosted in medium to high-grade metamorphic rocks of Barrovian upper amphibolite to granulite facies. The pegmatites are tabular, with N25o-30oW to N25o-45oE predominant strikes, and 30o-45o NE or NW dips. The pegmatites show heterogeneous, complex internal structure with variable textural patterns and mineral modes; the units of primary crystallization are border, wall, intermediate zones and quartz core, discrete muscovite and albite replacement bodies are always present. The mineral assemblages are characterized by the predominance of K-feldspar, quartz, plagioclase, muscovite and biotite; the accessory minerals are Grt-Brl-Vrm-Aln-Mnz-Ep. Based on mineralogical, geochemical, structural and para-genetic attributes, the pegmat...
An unusual coarse-grained sample of mitridatite from a granitic pegmatite is described. The miner... more An unusual coarse-grained sample of mitridatite from a granitic pegmatite is described. The mineral was found in three pieces of a fragmented nodule approximately 10-20 cm, in the dumps of the San Luis mine, La Florida, Argentina. Similar nodules of primary triphylite-lithiophilite altered to ferrisicklerite and dufrenite are included in quartz from the core-margin association of the rare-element-enriched, spodumene-bearing granitic pegmatite. Mitridatite is very dark green, almost black, has a dull pale green streak and deep ruby red internal reflections. It has very good {100} cleavage, vitreous luster, a density of 3.221 g/cm 3 and a Mohs hardness of 5 to 5.5. The three strongest X-ray powder-diffraction lines [d in Aa(I)(hkl)] are: 8.70(100)(200), 2.901(80)(600), and 2.176(60)(800). The refined unit-cell parameters are: a 17.505(1), b 19.327(3), c 11.261(6) Aa, beta 96.05(1) degrees , V 3788(1) Aa 3 . Optically, mitridatite is transparent, with X pale green, almost colorless, Y ...
... Geochemistry of K-feldspar and Muscovite in Rare-element Pegmatites and Granites from the Tot... more ... Geochemistry of K-feldspar and Muscovite in Rare-element Pegmatites and Granites from the Totoral Pegmatite Field, San Luis, Argentina. ... San Luis I pegmatite has been synkinematically intruded and folded during a strong compressional event. ...
Hureaulite, Mn +2 5 (H 2 O) 4 (PO 3 (OH)) 2 (PO 4 ) 2 , from different deposits of the Totoral pe... more Hureaulite, Mn +2 5 (H 2 O) 4 (PO 3 (OH)) 2 (PO 4 ) 2 , from different deposits of the Totoral pegmatitic field, San Luis. Hureaulite, a hydrated manganese (II) phosphate mineral, has been found in three different pegmatites of the Totoral pegmatitic field, San Luis ranges, Argentina. In Santa Ana mine, a berillium-bearing pegmatite located in the Cerro La Torre group, this phosphate mineral occurs associa- ted with eosphorite as little prismatic idiomorphic crystals implanted on sicklerite exfoliation surfaces, and originated by the hydrothermal altera- tion of primary lithiophilite. In Ranquel, a berillium-bearing pegmatite located in the Loma Alta group, hureaulite is associated with ferrisicklerite, purpurite, phosphosiderite, strengite, reddingite, meta-autunite, eosphorite, vivianite and hydroxil-apatite and has been formed by hydrothermal reworking of triphylite; the crystals are 5 mm in length and show typical monoclinic forms. In San Luis II, a lithium-bearing pegmatite loc...
espanolLa yacencia de cacoxenita, Fe3+24AlO6(PO4)17(OH)12•75H2O, ha sido determinada en la pegmat... more espanolLa yacencia de cacoxenita, Fe3+24AlO6(PO4)17(OH)12•75H2O, ha sido determinada en la pegmatita berilifera Ranquel, grupo Loma Alta, distrito pegmatitico Totoral, San Luis, Argentina. Este fosfato mineral ocurre como agregados esferuliticos amarillos a pardo amarillentos, con estructura interna en forma de rosetas, alojados entre cristales de vivianita o tapizando pequenas cavidades sobre otros fosfatos metasomaticos o hidrotermales. Opticamente, el mineral es uniaxico (+), con ω = 1,572 y e = 1,642; su pleocroismo es debil, con O = amarillo palido y E = pardo amarillento. Su difractograma de rayos X muestra como lineas mas intensas [dobs en A(I/I0)(hkl)]: 11,88(100)(200), 13,78(18)(110) y 6,83(12)(121, 211). Los parametros de celda son: a 27,531(8) A, c 10,549(1) A y V 6927(2) A3, con c/a 0.383. La composicion quimica, basada en analisis EDS y WDX, muestra P, O, Fe, Mn y Al. Cacoxenita ha cristalizado en un estadio hidrotermal tardio bajo condiciones de alta oxidacion EnglishC...
San Guillermo, Santa Amalia, Andacollo and El Chanar muscovite-bearing pegmatites from Balilla an... more San Guillermo, Santa Amalia, Andacollo and El Chanar muscovite-bearing pegmatites from Balilla and Aurora pegmatite groups, are located between 30o30´ and 30o47´S and 67o29´ and 67o43´W, in the Sierra de Valle Fertil, northwestern Argentina. The deposits are hosted in medium to high-grade metamorphic rocks of Barrovian upper amphibolite to granulite facies. The pegmatites are tabular, with N25o-30oW to N25o-45oE predominant strikes, and 30o-45o NE or NW dips. The pegmatites show heterogeneous, complex internal structure with variable textural patterns and mineral modes; the units of primary crystallization are border, wall, intermediate zones and quartz core, discrete muscovite and albite replacement bodies are always present. The mineral assemblages are characterized by the predominance of K-feldspar, quartz, plagioclase, muscovite and biotite; the accessory minerals are Grt-Brl-Vrm-Aln-Mnz-Ep. Based on mineralogical, geochemical, structural and para-genetic attributes, the pegmat...
An unusual coarse-grained sample of mitridatite from a granitic pegmatite is described. The miner... more An unusual coarse-grained sample of mitridatite from a granitic pegmatite is described. The mineral was found in three pieces of a fragmented nodule approximately 10-20 cm, in the dumps of the San Luis mine, La Florida, Argentina. Similar nodules of primary triphylite-lithiophilite altered to ferrisicklerite and dufrenite are included in quartz from the core-margin association of the rare-element-enriched, spodumene-bearing granitic pegmatite. Mitridatite is very dark green, almost black, has a dull pale green streak and deep ruby red internal reflections. It has very good {100} cleavage, vitreous luster, a density of 3.221 g/cm 3 and a Mohs hardness of 5 to 5.5. The three strongest X-ray powder-diffraction lines [d in Aa(I)(hkl)] are: 8.70(100)(200), 2.901(80)(600), and 2.176(60)(800). The refined unit-cell parameters are: a 17.505(1), b 19.327(3), c 11.261(6) Aa, beta 96.05(1) degrees , V 3788(1) Aa 3 . Optically, mitridatite is transparent, with X pale green, almost colorless, Y ...
... Geochemistry of K-feldspar and Muscovite in Rare-element Pegmatites and Granites from the Tot... more ... Geochemistry of K-feldspar and Muscovite in Rare-element Pegmatites and Granites from the Totoral Pegmatite Field, San Luis, Argentina. ... San Luis I pegmatite has been synkinematically intruded and folded during a strong compressional event. ...
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