minerals Article Kishonite, VH2, and Oreillyite, Cr2N, Two New Minerals from the Corundum Xenocrysts of Mt Carmel, Northern Israel Luca Bindi 1,* , Fernando Cámara 2 , Sarah E. M. Gain 3,4 , William L. Griffin 3 , Jin-Xiang Huang 3 , Martin Saunders 4 and Vered Toledo 5 1 Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via G. La Pira 4, I-50121 Firenze, Italy 2 Dipartimento di Scienze della Terra ‘A. Desio’, Università degli Studi di Milano, Via L. Mangiagalli 34, I-20133 Milano, Italy; [email protected] 3 Australian Research Council Centre of Excellence for Core to Crust Fluid Systems (CCFS) and GEMOC, Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia; [email protected] (S.E.M.G.); bill.griffi[email protected] (W.L.G.); [email protected] (J.-X.H.) 4 Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA 6009, Australia; [email protected] 5 Shefa Gems, Netanya 4210602, Israel; [email protected] * Correspondence: luca.bindi@unifi.it; Tel.: +39-055-2757532 Received: 17 November 2020; Accepted: 11 December 2020; Published: 13 December 2020 Abstract: Here, we describe two new minerals, kishonite (VH2) and oreillyite (Cr2N), found in xenoliths occurring in pyroclastic ejecta of small Cretaceous basaltic volcanoes exposed on Mount Carmel, Northern Israel. Kishonite was studied by single-crystal X-ray diffraction and was found to be cubic, space group Fm3m, with a = 4.2680(10) Å, V = 77.75(3) Å3, and Z = 4. Oreillyite was studied by both single-crystal X-ray diffraction and transmission electron microscopy and was found to be trigonal, space group P31m, with a = 4.7853(5) Å, c = 4.4630(6) Å, V = 88.51 Å3, and Z = 3. The presence of such a mineralization in these xenoliths supports the idea of the presence of reduced fluids in the sublithospheric mantle influencing the transport of volatile species (e.g., C, H) from the deep Earth to the surface. The minerals and their names have been approved by the Commission of New Minerals, Nomenclature and Classification of the International Mineralogical Association (No. 2020-023 and 2020-030a). Keywords: kishonite; oreillyite; hydride; nitride; corundum xenolith; reducing conditions; Mt Carmel; Israel 1. Introduction The study of the xenoliths occurring in pyroclastic ejecta of small Cretaceous basaltic volcanoes exposed on Mt Carmel [1–8] has revealed a very peculiar, exotic and ultra-reduced mineral assemblage reflecting the interaction of deep-seated basaltic magmas with mantle-derived CH4 + H2 at high fluid/melt ratios. During these ongoing studies, two new minerals, kishonite (VH2) and oreillyite (Cr2N) have been identified and are described here. The sample containing kishonite was recovered from bulk alluvial samples in the Kishon Mid Reach Zone 2. These are part of a xenolith assemblage that includes coarse-grained aggregates of 0 hibonite + grossite + spinel assemblages that carry inclusions of V and V-Al alloys, indicating f O2 down to DIW 9 [4]. ≤ − Minerals 2020, 10, 1118; doi:10.3390/min10121118 www.mdpi.com/journal/minerals Minerals 2020, 10, 1118 2 of 10 Minerals 2020, 10, x FOR PEER REVIEW 2 of 11 The sample containing oreillyite was recovered from the Kishon Mid Reach Zone 1 and consists of a 1.7 mmThe crystal sample of containing corundum oreillyite with a hollow was recovered centre and from raised the Kishon rims, indicatingMid Reach hopperZone 1 and growth, consists and it hasof an a 1.7 intense mm purple-redcrystal of corundum colour [5 ].with a hollow centre and raised rims, indicating hopper growth, andThe it has name an intense kishonite purple is for-red the colour Kishon [5]. river, which drains Mt Carmel and enters the sea near Haifa inThe Northern name kishonite Israel (andis for the where Kishon the river, placer which gemstone drains depositsMt Carmel with and theenters studied the sea xenoliths near Haifa are located),in Northern whereas Israel oreillyite (and where honours the placer Suzanne gemstone O’Reilly deposits (born 1946),with the professor studied in xenoliths Geology are at loc Macquarieated), University,whereas oreillyite Sydney, Australia,honours Suzanne Director ofO’Reilly the ARC (born National 1946), Keyprofessor Centre in for Geology Geochemical at Macquarie Evolution andUniversity, Metallogeny Sydney, of Continents Australia, Director (GEMOC) of the and ARC Director National of the Key ARC Centre Centre for Geochemical of Excellence Evolution for Core to Crustand FluidMetallogeny Systems of (CCFS). Continents (GEMOC) and Director of the ARC Centre of Excellence for Core to CrustBoth Fluid new Systems minerals (CCFS). and mineral names have been approved by the Commission on New Minerals, NomenclatureBoth new and minerals Classification and mineral of the names International have been Mineralogical approved Associationby the Commission (No. 2020-023 on New and 2020-030aMinerals, for Nomenclature kishonite and and oreillyite, Classification respectively). of the International Holotypes Mineralogical are deposited Association in the collections (No. 2020 of- the Museo023 and di Storia 2020- Naturale,030a for kishonite Universit àanddegli oreillyite, Studi di respectively). Firenze, Firenze, Holotypes Italy, catalogue are deposited number in 3364the /I. collections of the Museo di Storia Naturale, Università degli Studi di Firenze, Firenze, Italy, catalogue Oreillyite is also deposited at the Centre for Microscopy, Characterization and Analysis, The University number 3364/I. Oreillyite is also deposited at the Centre for Microscopy, Characterization and of Western Australia, Australia, catalogue number 1174-C_FF. Analysis, The University of Western Australia, Australia, catalogue number 1174-C_FF. 2. Description and Physical Properties 2. Description and Physical Properties Kishonite occurs as one subhedral single crystal, 17 25 38 µm (Figure1), which is the holotype Kishonite occurs as one subhedral single crystal, 17 × 25 ×× 38 μm (Figure 1), which is the holotype material. It is opaque. Colour, luster, streak, hardness, tenacity, cleavage, fracture, density, and optical material. It is opaque. Colour, luster, streak, hardness, tenacity, cleavage, fracture, density, and properties could not be determined because of the small grain size. optical properties could not be determined because of the small grain size. FigureFigure 1. 1.Images Images of the the rock rock fragment fragment from from Mt MtCarmel. Carmel. (a) Back (a)-scattered Back-scattered electron electron (BSE) image (BSE) of image the ofhibonite the hibonite–grossite–spinel–grossite–spinel aggregate aggregate studied. studied. The red Thebox redindicates box indicates the region the enlarged region in enlarged (b) and ( inc),( b) andwhich (c), whichreports reports X-ray compositional X-ray compositional maps, and maps, the green and thebox greenshows box the showsregion enlarged the region in enlarged(d) a BSE in image; arrows mark the (V,Al)-alloys and the VH2 fragment (kishonite) that was sampled. (e) (d) a BSE image; arrows mark the (V,Al)-alloys and the VH2 fragment (kishonite) that was sampled. Transmitted-light photo (plane polars) of the same rock sample, showing inclusions of metallic (e) Transmitted-light photo (plane polars) of the same rock sample, showing inclusions of metallic vanadium in platy hibonite crystals. (f) BSE image of a typical hibonite crystal showing the zonal vanadium in platy hibonite crystals. (f) BSE image of a typical hibonite crystal showing the zonal distribution of vanadium and (V,Al)-alloys on crystal faces. Crystal orientation is shown by the blue distribution of vanadium and (V,Al)-alloys on crystal faces. Crystal orientation is shown by the blue hexagonal prism. hexagonal prism. −3 Calculated density is 4.523 g·cm ,3 using the empirical formula and X-ray single-crystal data (see Calculated density is 4.523 g cm− , using the empirical formula and X-ray single-crystal data below). Kishonite is associated with· hibonite, grossite, spinel, vanadium, and V-Al alloys. A more (see below). Kishonite is associated with hibonite, grossite, spinel, vanadium, and V-Al alloys. A more detailed description of the kishonite occurrence is given by Bindi et al. [9]. detailed description of the kishonite occurrence is given by Bindi et al. [9]. Oreillyite occurs as one subhedral volume sandwiched between corundum and native Oreillyite occurs as one subhedral volume sandwiched between corundum and native chromium chromium (Figure 2), which is the holotype material. (Figure2), which is the holotype material. Minerals 2020, 10, 1118 3 of 10 Figure 2. Images of sample 1174C. (a) BSE image and transmitted-light photomicrograph showing colour, and distribution of highest-Cr parts (light areas in BSE). Note ball of chromium (Cr0) on edge of crystal. (b) 3D oblique view and compositional map of the surface of 1174C before sectioning. Rough dark green in lower part of the image is the ruby; smooth dark green in the upper part is kahlenbergite (KAl11O17). Small bright grains along rim of crystal in middle of image are Ni-bearing iron. Bright pink-purple “mushrooms” are chromium. (c) Phase map and Al map of the contact between the largest Cr ball, showing higher Cr (lower Al) toward the Cr ball, and the compositional granularity of the high-Cr zone. (d) TEM-BSE image and element maps of FIB foil across contact between chromium and Cr-rich corundum, separated by a zone of oreillyite (scale bar indicates 2 µm). Note granularity in the Cr and Al maps of the corundum, interpreted as the result of spinodal breakdown. Colour, lustre, streak, hardness, tenacity, cleavage, fracture, density, and optical properties could not be determined because of the small grain size. Calculated density is 6.64 g cm 3 using the ideal · − formula and the unit-cell volume of the triple ordered cell (Z = 3; see below). 3. Chemical Composition Quantitative elemental microanalyses of the type grain of kishonite were carried out using a CAMECA 100 electron microprobe (WDS mode, 15 kV and 10 nA, 1 µm beam size, counting times × 20 s for peak and 10 s for background; Gennevilliers, France).