Novas ocorrências de euclásio em Minas Gerais.
Since the 18th century euclase in
Brazil has been mined mainly in the reknowed mineralogical district of
Ouro Preto, Minas Gerais. Three new deposits were more recently
discovered in the same state: (1) In 1979-80 garimpeiros
exploited about 10 kg of yellow gem-quality material and specimens for
collectors, but the location of the source remained unknown in the
geologic literature. It is situated near the small village of Olhos
D'Água, in Bocaiúva district, northwestern Minas Gerais; (2) Soon after
the first exploitation, another euclase occurrence was discovered in the
same region, some 25 km NNW of Itacambira. About 3 kg de grey-blue
euclase, mostly collection specimens, have been produced. (3)
Occurrences in the Gouveia district were detected by the authors during
alluvial diamond prospecting. In this area the specimens have only
mineralogical importance. In all localities, the mineral occurs
disseminated and/or concentrated in pockets in the small feldspathic
zone of pegmatoid quartz veins truncating quartzites of the Espinhaço
Supergroup (Bocaiúva and Itacambira deposits) or schist and granitic
rocks of the pre-Espinhaço Complex (Gouveia occurrences).
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