The ideal formula for flurlite has been revised to Zn4Fe3+(PO4)3(OH)2(H2O)7·2H2O and its Mn analogue, manganflurlite (IMA2017-076), ZnMn32+Fe3+(PO4)3(OH)2(H2O)7·2H2O has been found on two specimens of phosphophyllite from the Hagendorf-Süd pegmatite, Oberpfalz, Bavaria, Germany. Manganflurlite occurs as long, very thin, rectangular laths, up to 0.5 mm long and less than 10 μm thick. Laths are elongated on [100], flattened on {001} and exhibit the forms {1 0 0}, {0 1 0} and {0 0 1}. The mineral is orange brown in colour and transparent with a vitreous iridescent lustre and buff streak. Crystals are flexible and elastic with irregular fracture, and three cleavages: perfect on {0 0 1}, good on {1 0 0} and {0 1 0}. The Mohs’ hardness is ca. 2½. The measured density is 2.73(2) g cm−3. At room temperature, the mineral dissolves rapidly in dilute HCl. Optically, manganflurlite is biaxial (–), with α = 1.623(calc), β = 1.649(2), γ = 1.673(2) (white light); 2V = 86(1)°. The dispersion is r > v, slight; the optical orientation is X = c, Y = b, Z = a. The pleochroism is X = pale yellow brown, Y = orange brown, Z = light yellow brown, Y > Z > X. Electron microprobe analyses for crystals from the holotype specimen gave the empirical formula Zn(Mn1.512+Fe0.692+Zn0.68Mg0.08)Σ2.96(Fe0.953+Al0.05)Σ1.00(PO4)3(OH)1.92(H2O)9.08. Manganflurlite is monoclinic, P21/m, a = 6.4546(8), b = 11.1502(9), c = 13.1630(10) Å, β = 99.829(5)°, V = 933.44(16) Å3 and Z = 2. The crystal structure, refined including all protons to Robs = 0.034 for 2219 observed reflections [I > 3σI], shows the mineral to be isostructural with flurlite. These minerals have a heteropolyhedral layer structure that is a topological isomer of the schoonerite structure.

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