MINERALOGICAL CHARACTERIZATION OF AMAZONITES FROM SERRA DO PINHEIRO, SERTÂNIA (PE), BRAZIL

Glenda Lira Santos, Eduardo Toshiyuki Fagundes Watanabe, José Ferreira de Araújo Neto, Igor Manoel Belo de Albuquerque e Souza, Sandra de Brito Barreto

Resumo


The amazonite from Serra do Pinheiro is the only occurrence of this mineral found registered in the Pernambuco state, Brazil. This mineralization stands out for its specific geological environment and potential use as a gemmological specimen. This paper includes the spectroscopic and chemical data from this mineral and how it presents itself. The studied amazonite is found scattered in pegmatite veins, hosted in a peralkaline granodiorite from Serra do Pinheiro. It presents pale green colour, density of 2.5 g/cm³ and prismatic habit. This mineral’s crystals were investigated by x-ray diffraction, x-ray fluorescence, infrared spectroscopy by attenuated total reflectance, differential thermal and thermogravimetric analysis, infrared absorption spectroscopy and reflectance spectroscopy. This amazonite is characterized by a microcline with a low degree of Al/Si order, containing approximately 325 ppm of lead and 307 ppm of iron, presenting absorption bands related to these elements which are chromophores and responsible for its pale green colour.

Palavras-chave


amazonite, Serra do Pinheiro, chemical and spectroscopic characterization, pale green colour

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DOI: https://doi.org/10.18190/1980-8208/estudosgeologicos.v27n1p95-107

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