دانلود کتاب Mineralogia e Zoneografia do Campo Pergmatítico da Golconda - Município de Governador Valadares

The pegmatites of the Golconda Region occur preferen-tially embedded in the biotite and cataclastic gnaisses inserted with beds of amphibolites Precambrian in age related to the Paraíba do Sul Group. Two very distinct types occur. One characterized by simple mineralogy and structure, and the other, by complex mineralogy and zoned structure.

Pegmatites of the first type occur in geomorphologic marsh unit and those of the second type occur predominantly in the hills (Serra dos Ferreiras) and, when they do not appear zoned, they show themselves albitized to divide the área into two dif-ferent domains.

The description of identified minerais and data about the orientation of pegmatites, forms, sizes and relation with the wall rock, are presented in the text and are included in the index cards of the individual description of the pegmatites that constitute the attachment.

It must be noted that the principal mining activity of the area is primitive mining for columbite-tantalite and gems. Many are the remaining mining sites from the 40's and 50´s presently abandoned and/or completely caved in, obstructing the direct access for study of its mineralogy, which obliged the use of panning for concentration of the wastes and posterior processing in laborators.

The pegmatites prõduct feldsparr mica, beryl, columbite, tantalite and gems.