An аquarelle effect in colouring of “plagioclase-amazonite”

Ivanov M. A., Vasilev E. A., Galankina O. L.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2021. V. 150. N 2. P. 83-91

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Language: Russian 


The term “plagioclase-amazonite” has been for the first time put in application by S.A. Rudenko and A.Ya. Vokhmentsev in 1969 as the name for bluish-green variety of oligoclase. The article analyses location of bluish-green oligoclase (plagioclase-amazonite) in plagioclase pegmatites of the North-Baikal muscovite-bearing province. Origin of the mineral colouring was studied by optical and electron microscopic, spectroscopic (Raman) and electron microprobe methods. It has been found that the mineral color is not determined by the nonisomorphic incorporation of copper atoms into its structure, as it was assumed previously, but has an allochromatic nature due to the effect of reflection and transmission by multiple microinclusions of chrysocolla formed while hypergenic alteration of bornite, chalcosine, and other copper sulfides in near-surface conditions of chemical weathering of pegmatite bodies

Keywords: plagioclase-amazonite, plagioclase pegmatites, chalcopyrite, bornite, chalcosine, chrysocolla, aquarelle effect