Abstract A new arrojadite-group mineral manganoarrojadite-(KNa), ideally KNa5MnFe13Al(PO4)11(PO3OH)(OH)2, was found in a phosphate-bearing granite pegmatite at the Palermo No. 1 mine, New Hampshire, USA. It forms anhedral grains up to 1 × 1.5 cm in size combined in aggregates with vivianite, goyazite, quartz and calcite. The mineral is olive green with a pale green streak and vitreous to greasy lustre. The cleavage is good in one direction. The Mohs hardness is 4½. Dcalc is 3.53 g/cm3. Manganoarrojadite-(KNa) is optically biaxial (–), α = 1.658(2), β = 1.666(2), γ = 1.670(2), 2Vmeas. = 67(1)° and 2Vcalc. = 70° (589 nm). The infrared spectrum is reported. The composition (wt.%) is Na2O 6.97, K2O 1.78, CaO 0.31, MgO 2.17, MnO 12.30, FeO 31.17, Al2O3 2.43, P2O5 40.48, F 0.30, H2O 1.32, O = F2 –0.13, total 99.10. The empirical formula calculated on the basis of 12 P and (O+OH+F) = 50 apfu is Na4.73K0.80Ca0.12Mg1.13Mn2+3.65Fe2+9.13Al1.00P12.00O46.59OH3.08F0.33. The ideal structural formula is A1KA2NaB1NaB2NaNa1,2Na2Na3□ CMnMFe13Al(PO4)11(PO3OH)W(OH)2. The mineral is monoclinic, Cc, a = 16.5345(3), b = 10.0406(2), c = 24.6261(5) Å, β = 105.891(2)°, V = 3932.09(14) Å3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 5.902(24)(202), 5.025(24)(020), 3.208(47)(206,$\;\bar{1}$32), 3.048(100)($\bar{5}$14, $\bar{4}$24), 2.758(24)($\bar{6}$02) and 2.704(70)(226). The crystal structure, refined from single-crystal X-ray diffraction data (R1 = 0.025), is of the arrojadite structure type. Manganoarrojadite-(KNa) is the first arrojadite-group mineral with Mn dominant on the site usually occupied by Ca and without Ca as the dominant cation at any cation site.

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Manganoarrojadite-(KNa), KNa5MnFe13Al(PO4)11(PO3OH)(OH)2，一种来自美国新罕布什尔州巴勒莫 1 号矿的新菱镁矿族矿物

摘要 在美国新罕布什尔州巴勒莫 1 号矿的含磷酸盐花岗岩伟晶岩中发现了一种新的菱铁矿类矿物锰菱铁矿-(KNa)，理想情况下为 KNa5MnFe13Al(PO4)11(PO3OH)(OH)2。它形成大小达 1 × 1.5 厘米的无面体颗粒，与紫云母、菱铁矿、石英和方解石聚集在一起。矿物呈橄榄绿色，带有淡绿色条纹和玻璃光泽至油脂光泽。解理在一个方向上是好的。莫氏硬度为 4½。Dcalc 为 3.53 g/cm3。Manganoarrojadite-(KNa) 是光学双轴 (–), α = 1.658(2), β = 1.666(2), γ = 1.670(2), 2Vmeas。= 67(1)° 和 2Vcalc。= 70°（589 纳米）。报告了红外光谱。组成 (wt.%) 为 Na2O 6.97, K2O 1.78, CaO 0.31, MgO 2.17, MnO 12.30, FeO 31.17, Al2O3 2.43, P2O5 40.48, F 0.30, 总 H2O. = 1,20.9.0.1,20. 根据12 P和(O+OH+F)=50apfu计算的经验公式为Na4.73K0.80Ca0.12Mg1.13Mn2+3.65Fe2+9.13Al1.00P12.00O46.59OH3.08F0.33。理想的结构式为A1KA2NaB1NaB2NaNa1,2Na2Na3□CMnMFe13Al(PO4)11(PO3OH)W(OH)2。矿物为单斜晶系，Cc，a = 16.5345(3)，b = 10.0406(2)，c = 24.6261(5) Å，β = 105.891(2)°，V = 3932.09(14) Å3，Z = 4。粉末 X 射线衍射图的最强反射 [d,Å(I)(hkl)] 为：5.902(24)(202), 5.025(24)(020), 3.208(47)(206,$\;\ bar{1}$32)、3.048(100)($\bar{5}$14、$\bar{4}$24)、2.758(24)($\bar{6}$02) 和 2.704(70)(226) . 从单晶 X 射线衍射数据 (R1 = 0.025) 精炼的晶体结构属于菱铁矿结构类型。