Tauler, EsperançaProenza, Joaquín A.Galí Medina, SalvadorLewis , John F.Labrador Carrasco, ManuelGarcía Romero, EmiliaSúarez Barrios, MercedesLongo, FranciscoBloise, Giovanni2023-06-202023-06-2020090009-855810.1180/claymin.2009.044.4.435https://hdl.handle.net/20.500.14352/50683New chemical and structural data on sepiolite-falcondoite in garnierite veins from the Falcondo Ni-laterite deposits, central Dominican Republic, are reported. Samples of Ni-sepiolitefalcondoite vary in colour from whitish green to green depending on the NiO content (wt.%) and the amount of silica present. The texture is normally schistose and friable but samples with considerable quartz and/or amorphous silica are compact and hard. Back-scattered electron images indicate that the samples are composed of at least three generations of Ni-sepiolite-falcondoite. The extreme refined cell parameters for Ni-sepiolite-falcondoite vary from 13.400(2), 27.006(4), 5.273(1) A˚ to 13.340(3), 27.001(6), 5.267(1) A˚ (space group Pncn). As the Ni content increases there is a small reduction in the a parameter. Chemical compositions determined by electron probe microanalysis cover a large interval of the Ni-sepiolite-falcondoite solid solution (Fal3 and Fal77). Individual samples show a considerable range in composition with the widest range determined in one sample from 4.63 to 22.40 wt.% NiO.engjournal articlehttp://www.minersoc.org/clayminm.htmlopen access549.6(729.3)Ni-sepioliteFalcondoiteGarnieriteCrystal chemistryFalcondoNi-lateritesDominican RepublicMineralogía (Geología)2506.11 Mineralogía