Topic
Simpsonite
About: Simpsonite is a research topic. Over the lifetime, 4 publications have been published within this topic receiving 71 citations.
Papers
1 Jan 1992
TL;DR: In this article, the shape, extent and position of the two-phase field in the columbite quadrilateral were established empirically by analyzing 45 ferrotapiolite-tantalite pairs from 12 granitic pegmatites.
Abstract: ABsrRAcr Compositions of 45 ferrotapiolite-tantalite pairs from 12 granitic pegmatites were analyzed by electnon microprobe to establish empirically the shape, extent and position of the two-phase field in the columbite quadrilateral. The field is perceptibly broader than that defined earlier on the basis of single-phase samples. The compositions of single phases located within the boundaries based on coexisting minerals are, under the conditions of crystallization, probably metastable. The two-phase field derived from coexisting minerals approximates an isothermal section through a pseudoquatemary solvus in the columbite quadrilateral through most of the coune of its boundaries, as defined by primary Nb.enriched ferrotapiolite - tantalite pairs from blocky zones and albitic units of their parent pegmatites. Extremely fractionated mineral pairs most enriched in Mn and Ta come from late associations replacing simpsonite; they crystallized at distinctly lower temperatures. Boundaries of the fwo-phase field are controlled by temperature,io2), structural state, impudries disturbing the 48206 stoichiometry. and probably pressure. All these factors require thorough experimental reinvestigation.
57 citations
TL;DR: A study of the Alto do Giz, near Equador, Rio Grande do Norte, Brazil, reveals an interesting series of tantalum minerals including the rare aluminum tantalate, simpsonite, which is also found in white crystals at this mine and in buff-colored crystals at the Onca Mine.
Abstract: A study of the Alto do Giz, near Equador, Rio Grande do Norte, Brazil, reveals an interesting series of tantalum minerals including the rare aluminum tantalate, simpsonite. Crystals of this mineral are yellow brown, hexagonal in outline; c = .60978. It belongs to the hexagonal dipyramidal class C 6h . Hardness 7½, specific gravity is 6.81. It fluoresces blue to white in a cold quartz mercury vapor lamp with a filter. It is also found in white crystals at this mine and in buff-colored crystals at the Onca Mine, some miles away. It appears to be a replacement mineral of a short complex pegmatite sequence, crystallizing after microlite and tantalite.
10 citations
TL;DR: The hexagonal mineral simpsonite, an oxide of aluminum and tantalum or a tantalate from Tabba Tabba in Western Australia, was described and named by Bowley in 1939 Taylor furnished Laue and Bragg x-ray data at the same time as discussed by the authors.
Abstract: The hexagonal mineral simpsonite, an oxide of aluminum and tantalum or a tantalate from Tabba Tabba in Western Australia, was described and named by Bowley in 1939 Taylor furnished Laue and Bragg x-ray data at the same time The mineral as originally identified was assigned a complex formula based upon the analysis of material consisting of a mixture of microlite and simpsonite Since the original description appeared, occurrences of an aluminum tantalate have been found in two localities in Brazil along the boundary between the states of Paraiba and Rio Grande do Norte and in Southern Rhodesia at Bikita X-ray-diffraction studies and optical examination have shown that the fundamental aluminum tantalate is the same in the materials from Western Australia, Brazil, and Southern Rhodesia In addition Laue photographs have been obtained and correlated with Taylor9s original x-ray data Rotation photographs have been utilized in establishing the lattice constants
7 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2005 | 1 |
| 1992 | 1 |
| 1945 | 2 |