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ThFeNb2O8    (IMA2018-088)

Mineral was known in the past as Wernerite or later Samarskite-Y from Laacher See area. Samarskite Group minerals mostly linked to granite pegmatites. In analysis of elements Samarskite-Y contains high Fe content, should be see literature around 4-23% Fe sum all. The formulation is complex and synthetic Samarskite-Y has YFe2Nb5O18.

Suspicious from Samarskite-Y in EDX analytic had been the high Th content. Seems like also Ishikawaite. But for Ishikawaite the content of U should be much higher. [quote & thanks to G.Blaß]

With further analytics regarding the Thorium content a new structure type could be determinated an subscribed as Ekebergite. (Kjellman, J., Pay Gómez, C., Lazor, P., Majka, J., Stanley, C. and Najorka, J. (2018) Ekebergite, IMA 2018-088. CNMNC Newsletter No. 46, December 2018, page xxxx; Mineralogical Magazine, 82, xxxx–xxxx).

Ekebergite is in paragenetic mostly with Magnetite but also with typical black Phlogopite mica. His crystals are tabular and holey, often skeletal. They are based in younger geological formations so internal radioactivity has not yet destroyed the angular form of the crystals.

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