Natural phosphides - the minerals containing phosphorus in a redox state lower than zero – are common constituents of meteorites but virtually unknown on the Earth. Herein we present the first rich occurrence of iron-nickel phosphides of terrestrial origin. Phosphide-bearing rocks are exposed in three localities in the surroundings of the Dead Sea, Levant: in the northern Negev Desert, Israel and Transjordan Plateau, south of Amman, Jordan. Seven minerals from the ternary Fe-Ni-P system have been identified with five of them, NiP₂, Ni₅P₄, Ni₂P, FeP and FeP₂, previously unknown in nature. The results of the present study could provide a new insight on the terrestrial origin of natural phosphides – the most likely source of reactive prebiotic phosphorus at the times of the early Earth.

Allabogdanite, (Fe,Ni)₂P, is a new mineral from the Onello iron meteorite (Ni-rich ataxite). It occurs as thin lamellar crystals disseminated in plessite. Associated minerals are nickelphosphide, schreibersite, awaruite, and graphite. Crystals of the mineral, up to 0.4 × 0.1 × 0.01 mm, are flattened on (001) with dominant {001} faces, and other faces that are probably {110} and {100}. Mirror twinning resembling that of gypsum is common, with possible twin composition plane {110}. Crystals are light straw-yellow with bright metallic luster. Polished (001) sections look silvery-white against an epoxy background. In reflected light in air, the mineral has a creamy color, with distinct anisotropy from light to dark creamy tint. No bireflectance was observed. R₁/R2 (λ, nm) in air: 48.4/37.2(440), 46.7/36.8(460), 47.0/37.6(480), 47.5/38.1(500), 47.6/38.8(520), 48.2/39.2(540), 49.0/39.9(560), 49.6/40.7(580), 50.1/41.6(600), 50.5/41.9(620), 51.9/43.0(640), 52.3/44.3(660), 53.3/45.0(680), 54.4/46.2(700). No cleavage or parting was observed. Moh’s hardness is 5–6; the mineral is very brittle, and its calculated density 7.10 g/cm³. Its chemical composition (determined by microprobe methods, average of nine analyses) is: Fe 57.7, Ni 20.7, Co 1.4, P 20.4, Total 100.2 wt%, corresponding to (Fe_1.51Ni_0.50Co_0.03)_2.04P_0.96 (three atoms per formula unit). Crystal structure: R1 = 0.040 for 138 unique observed (|Fo|≥ 4σ_F) reflections. Orthorhombic, Pnma, unit-cell parameters refined from powder data: a = 5.748(2), b = 3.548(1), c = 6.661(2) Å, V = 135.8(1), ų, Z = 4; unit-cell parameters refined from single-crystal data: a = 5.792(7), b = 3.564(4), c = 6.691(8) Å, and V = 138.1(3) ų. Strongest reflections in the X-ray powder diffraction pattern are [d in Å, (I) (hkl)]: 2.238(100)(112), 2.120(80)(211), 2.073(70)(103), 1.884(50)(013), 1.843(40)(301), 1.788(40)(113), 1.774(40)(020). The mineral is named for Alla Bogdanova, Geological Institute, Kola Science Centre of Russian Academy of Sciences.

Rudashevskyite, Fe-dominant analogue of sphalerite, is an accessory phase in the Indarch meteorite (enstatite chondrite, EH4). It occurs as xenomorphic polycrystalline grains, 5–120 μm in size, associated with clinoenstatite, kamacite, troilite, oldhamite, niningerite, schreibersite, and roedderite. Macroscopically, rudashevskyite is black with resinous luster. In reflected light, it is gray with brownish tint. Isotropic, no internal reflections. Reflectance in air (%, λ): 19.5(400), 19.5(420), 19.5(440), 19.5(460), 19.6(470), 19.8(480), 19.8(500), 19.9(520), 20.2(540), 20.3(546), 20.5(560), 20.7(580), 20.8(589), 20.9(600), 20.9(620), 21.1(640), 21.1(650), 21.1(660), 21.1(680), and 21.2(700). Brittle. D_c 3.79 g/cm³. VHN 353 kg/mm². Chemical composition (electron microprobe, average of 31 analyses on 11 grains, wt%): Fe 37.1, Zn 24.7, Mn 2.4, Cu 0.4, S 35.3, total 99.9. Empirical formula (2 apfu): (Fe_0.61Zn_0.35Mn_0.04Cu_0.01)_{∑ = 1.00}S_1.00, ideally (Fe,Zn)S. Cubic, F4̅3m, a 5.426(2) Å, V 159.8 (2) ų, Z = 4. X-ray powder diffraction pattern (Debye-Scherrer, FeKα), [d(I)(hkl)]: 3.130(100)(111), 2.714(10)(200), 1.919(50)(220), 1.634(40)(311), 1.359(5)(400), 1.246(30)(331), 1.107(30)(422), 1.045(30)(511, 333). Crystal structure: R₁ = 0.050 for 26 unique observed (|F_o| ≥ 4∑_F) reflections. It is named in honor for N.S. Rudashevsky, St. Petersburg, Russia, for his contributions to the study of ore minerals.

Hielscherite, ideally Ca₃Si(OH)₆(SO₄)(SO₃)·11H₂O, (IMA 2011-037) is the first ettringite-group mineral with essential sulfite. We have identified a continuous natural solid-solution series from endmember thaumasite, Ca₃Si(OH)₆(SO₄)(CO₃)·12H₂O, to a composition with at least 77 mol.% endmember hielscherite. In this series, the SO3:CO3 ratio is variable, whereas the SO₄ content remains constant. Compositions with more than 50 mol.% endmember hielscherite have only been found at Graulay quarry near Hillesheim in the western Eifel Mountains, Rhineland-Palatinate, where they occur with phillipsite-K, chabazite-Ca and gypsum in cavities in alkaline basalt. Sulfite-rich thaumasite has been found in hydrothermal assemblages in young alkaline basalts in two volcanic regions of Germany: it is widespread at Graulay quarry and occurs at Rother Kopf, Schellkopf and Bellerberg quarries in Eifel district; it has also been found at Zeilberg quarry, Franconia, Bavaria. Hielscherite forms matted fibrous aggregates up to 1 cm across and groups of acicular to prismatic hexagonal crystals up to 0.3 × 0.3 × 1.5 mm. Individual crystals are colourless and transparent with a vitreous lustre and crystal aggregates are white with a silky lustre. The Mohs hardness is 2–2½. Measured and calculated densities are D_meas = 1.82(3) and D_calc = 1.79 g cm^–3. Hielscherite is optically uniaxial (–), ω = 1.494(2), ε = 1.476(2). The mean chemical composition of holotype material (determined by electron microprobe for Ca, Al, Si, and S and gas chromatography for C, H and N, with the S⁴⁺:S⁶⁺ ratio from the crystal-structure data) is CaO 27.15, Al₂O₃ 2.33, SiO₂ 7.04, CO₂ 2.71, SO₂ 6.40, SO₃ 12.91, N₂O₅ 0.42, H₂O 39.22, total 98.18 wt.%. The empirical formula on the basis of 3 Ca atoms per formula unit is Ca₃(Si_0.73Al_0.28)_Σ1.01(OH)_5.71(SO₄)_1.00(SO₃)_0.62(CO₃)_0.38(NO₃)_0.05·10.63H₂O. The presence of sulfite was confirmed by crystal-structure analysis and infrared and X-ray absorption near edge structure spectra. The crystal structure of sulfite-rich thaumasite from Zeilberg quarry was solved by direct methods based on single-crystal X-ray diffraction data (R₁ = 0.064). The structure of hielscherite was refined using the Rietveld method (R_wp = 0.0317). Hielscherite is hexagonal, P6₃, a = 11.1178(2), c = 10.5381(2) Å, V = 1128.06(4) Å3 and Z = 2. The strongest reflections in the X-ray powder pattern [(d, Å (I)(hkl)] are: 9.62(100)(010,100); 5.551(50)(110); 4.616(37)(012,102); 3.823(64)(112); 3.436(25)(211), 2.742(38)(032,302), 2.528(37)(123,213), 2.180(35)(042,402;223). In both hielscherite and sulfite-rich thaumasite, pyramidal sulfite groups occupy the same site as trigonal carbonate groups, with analogous O sites, whereas tetrahedral sulfate groups occupy separate positions. Hielscherite is named in honour of the German mineral collector Klaus Hielscher (b. 1957).