Stronadelphite from Alkaline Rocks of the Konder Massif (Khabarovsk Krai)

This paper presents the characteristics of stronadelphite Sr 5 (PO 4 ) 3 F, identified in the eudialyte–aegirine–albite rocks of the Konder alkaline–ultrabasic massif (Khabarovsk krai). The mineral occurs as individual crystals up to 400 × 150 microns in size, associated with eudialyte, lamprophyllite, barytolamprophyllite, microcline, titanite, nepheline, strontium-rich fluorapatite, and other accessory minerals. Stronadelphite crystals are colorless and translucent. The chemical formula recalculated to 25 charge units is (Sr 4.21 Ca 0.61 Ba 0.07 Na 0.07 Fe 0.05 ) 5.01 (P 3.01 O 11.93 )F 1.14 . This mineral is similar in chemical composition to the stronadelphite from the alkaline rocks of the Kola Peninsula. The Raman spectrum of the studied stronadelphite generally coincides with the spectrum of the synthetic analog. The correctness of mineral identification was confirmed by electron backscatter diffraction (EBSD) analysis. An assumption that the mineral crystallized in the course of low-temperature hydrothermal alteration of alkaline rocks was made.