Vzácný allanpringit - produkt alterace fluorwavellitu z lomu Milina u Zaječova (Česká republika)

Abstract

A very rare phosphate allanpringite was found in the abandoned quarry Milina near Zaječov, Czech Republic in Ordovician sediments of the Barrandian area. Allanpringite forms yellow powder and earthy aggregates. In a more detailed study using SEM microscope, allanpringite forms rod-shaped and tabular crystals. Its origin is associated with alteration of fluorwavellite. Empirical formula of the allanprigite is (Fe2.70Al0.24)Σ2.94(PO4)2.00(OH)2.83·5H2O and refined unit-cell parameters are a 9.774(5), b 7.361(3), c 17.826(8) Å, β 92.2(6)° and V 1281.5(9) Å3. Allanpringite was found in association with jarosite, variscite and partly altered fluorwavellite.