Butlerita (Fe OH SO4 2H2O) de la mina Santa Elena, provincia de San Juan, Argentina

• Autores: Lorenzo Francisco Aristarain
• Localización: Revista del Museo Argentino de Ciencias Naturales, ISSN-e 1853-0400, ISSN 1514-5158, Vol. 1, Nº. 2, 1999, págs. 145-150
• Idioma: español
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  • Butlerite (Fe OH SO4 2H2O) from Santa Elena mine, province of San Juan, Argentina. Idiomorphic crystals of Butlerite from Santa Elena mine, Calingasta, San Juan, Argentina, were used for this study. Butlerite (Fe OH SO4 2H2O) has the following characteristics: monoclinic, Prismatic class, space group P 21/m; a = 6.499(1), b = 7.378(1), c = 5.848(1)Å, ß = 108º28'(5), a:b:c = 0.8809:1:0.7926, cell volume 265.98 Å3, Z=2. The transparent crystals are colorless to pale yellow, the fine aggregates are yellow orange, the streak is pale yellow, the luster is vitreous. The crystals are tabular, measuring up to 1 mm across; the predominant forms are {001}, {100}, {110}, {011}, and {101}. The strongest peaks in the X-ray powder diagram are, in Å: 4.98 (100), 3.165 (52), 3.597 (17), 3.234 (14), 2.495 (14), 4.74 (9), 4.43 (9). Butlerite is biaxial (+), a = 1.595(1), ß = 1.666(1), g = 1.743(1) Na light, 2 V 85º, Z = b, XÙ c = -17º, pleochroism X = colorless, Y = faint yellow, Z = light yelow, high birefringence, cleavage {100} very good, fragile, hardness 2 1/2, density 2.552 g/cm3 (meas.), 2.559 g/cm3 (calc.). Parabutlerite, the orthorhombic dimorph, dipyramidal class (2/m 2/m 2/m), spatial group Pmnb, is associated with butlerite.