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Keplerite is a new mineral, the Ca-dominant counterpart of the most abundant meteoritic phosphate, merrillite. The isomorphous series merrillite-keplerite, Ca 9 NaMg(PO 4 ) 7 -Ca 9 (Ca 0.5 □ 0.5 )Mg(PO ) 7 represents the main reservoir of phosphate phosphorus in the Solar System. Both minerals are related by the heterovalent substitution at the B-site of the crystal structure: 2Na + (merrillite) → Ca 2+ + □ (keplerite). The near-end-member keplerite of meteoritic origin occurs in the main-group pallasites and angrites. The detailed description of the mineral is made based on the Na-free type material from the Marjalahti meteorite (the main group pallasite). Terrestrial keplerite was discovered in the pyrometamorphic rocks of the Hatrurim Basin in the northern part of Negev desert, Israel. Keplerite grains in Marjalahti have an ovoidal to cloudy shape and reach 50 μm in size. The mineral is colorless, transparent with a vitreous luster. Cleavage was not observed. In transmitted light, keplerite is colorless and non-pleochroic. Uniaxial (−), ω 1.622(1), ε 1.619(1). Chemical composition (electron microprobe, wt.%): CaO 48.84; MgO 3.90; FeO 1.33; P 2 O 5 46.34, total 100.34. The empirical formula (O = 28 apfu) is: Ca 9.00 (Ca 0.33 Fe 2+ 0.20 □ 0.47 ) 1.00 Mg 1.04 P 6.97 O 28 .The ideal formula is Ca 9 (Ca 0.5 □ 0.5 )Mg(PO 4 ) 7 . Keplerite is trigonal, space group R3c, unit-cell parameters refined from single-crystal data are: a 10.3330(4), c 37.0668(24) Å, V 3427.4(3) Å 3 , Z = 6. The calculated density is 3.122 g cm -3 . The crystal structure has been solved and refined to R 1 = 0.039 based on 1577 unique observed reflections [I >2σ(I)]. A characteristic structural feature of keplerite is a partial (half-vacant) occupancy of the sixfold-coordinated B-site (denoted as CaIIA in the earlier works). The disorder caused by this cation vacancy is the most likely reason for the visually resolved splitting of the ν 1 (symmetric stretching) (PO 4 ) vibration mode in the Raman spectrum of keplerite. The mineral is an indicator of high-temperature environments characterized by extreme depletion of Na. The association of keplerite with "REE-merrillite" and stanfieldite evidences for the similarity of temperature conditions occurred in the Mottled Zone to those This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

Allabogdanite, (Fe,Ni)2P, is the only known natural high-pressure phase reported in the Fe–Ni–P system. The mineral, which was previously described from a single meteorite, the Onello iron, is now discovered in the Santa Catharina and Barbianello nickel-rich ataxites. The occurrence of allabogdanite in Santa Catharina, one of the largest and well-studied meteorites, suggests that this mineral is more common than was believed. The formation of allabogdanite-bearing phosphide assemblages in a given meteorite provides evidence that it experienced peak pressure of at least 8 GPa at a temperature above 800 °C. Since the pressure-temperature stability parameters of allabogdanite fall within the margins of the stishovite (rutile-type SiO2) stability area, the former can be employed as a convenient stishovite-grade indicator of significant impact events experienced by iron and stony-iron meteorites and their parent bodies.