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IMA 2017-048 = graftonite-(Ca); IMA 2017-050 = graftonite-(Mn) (3 replies)

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Reference:
▪ Pieczka, A., Hawthorne, F.C., Ball, N., Abdu, Y., Gołębiowska, B., Włodek, A., Żukrowski, J. (2018): Graftonite-(Mn), ideally M1MnM2,M3Fe2(PO4)2, and graftonite-(Ca), ideally M1CaM2,M3Fe2(PO4)2, two new minerals of the graftonite group from Poland. Mineralogical Magazine, 82, 1307-1322.

Abstract:
Two new minerals of the graftonite group, graftonite-(Mn), ideally M1MnM2,M3Fe2(PO4)2, and graftonite-(Ca), ideally M1CaM2,M3Fe2(PO4)2, were discovered in phosphate nodules of two beryl-columbite-phosphate pegmatites, respectively at Lutomia and Michałkowa in the Góry Sowie Block, Lower Silesia, SW Poland. Graftonite-(Mn) is pinkish brown, whereas graftonite-(Ca) shows more brownish coloration. Both minerals have a vitreous luster, a good cleavage. Graftonite-(Ca) was collected at Michałkowa, 50°45’N, 16°27’E, in the middle part of the Góry Sowie Block, ~70 km SW of Wrocław, on a small pegmatite dump, a relic of excavation in the 19th century as a source of quartz and feldspar. During this work, Websky (1868) found and described sarcopside (type locality, TL), associated with hureaulite, vivianite and an apatite-group mineral. The dump is located on the left site of the Dział Michałowski Range, on the right side of the Młynówka stream, about 100 m from the Zagórze Śląskie – Lubachów – Michałkowa – Pieszyce road. The original pegmatite vein, ~10–12 m in length and 2–4 m in thickness, with visible zoning (wall zone – graphic zone – blocky feldspar zone), was composed of albite, microcline, quartz, muscovite, biotite, schorl evolving to foitite, almandine, sillimanite, andalusite and phosphate minerals in nodules reaching a few centimeters in diameter (Łodziński and Sitarz, 2009). Graftonite-(Ca) was found in an outer zone of a small phosphate nodule (~2 cm in diameter) collected on the dump. The nodule was composed mainly of lamellar intergrowths of the primary magmatic phosphates: sarcopside and graftonite-(Mn), with minor triphylite oxidized topotactically to ferrisicklerite and heterosite. In this zone, the magmatic phosphates underwent intensive Na and Ca metasomatism and were replaced by wolfeite, alluaudite, maneckiite, fluor- and hydroxylapatite, in places forming fine-grained mosaics (Pieczka et al., 2017a). To date, ~50 phosphate minerals has been identified in the pegmatite (Grochowina, 2016), with such rare species as maneckiite (TL), wicksite, willieite, ferrowillieite, qingheiite-(Fe), maghagendorfite, hagendorfite, ferrohagendorfite, johnsomervilleite, lazulite, gormanite, childrenite, souzalite and arrojadite-(KNa). Łodziński and Sitarz (2009) mentioned also the presence of qingheiite, rosemaryite and simferite in nodules of the pegmatite, but these phosphates have not yet been confirmed by chemical analysis or X-ray diffraction.

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