New Minerals from Inclusions in Corundum Xenocrysts from Mt. Carmel, Israel: Magnéliite, Ziroite, Sassite, Mizraite-(Ce) and Yeite

Abstract

Our nanomineralogical investigation of melt inclusions in corundum xenocrysts from the Mt. Carmel area, Israel has revealed seven IMA-approved new minerals since 2021. We report here four new oxide minerals and one new alloy mineral. Magnéliite (Ti3+2Ti4+2O7; IMA 2021-111) occurs as subhedral crystals, ~4 μm in size, with alabandite, zirconolite, Ti,Al,Zr-oxide, and hibonite in corundum Grain 767-1. Magnéliite has an empirical formula (Ti3+1.66Al0.13Ti4+0.15Mg0.10Ca0.01Sc0.01)Σ2.06 (Ti4+1.93Zr0.08)Σ2.01O7 and the triclinic P1¯ Ti4O7-type structure with the cell parameters: a = 5.60(1) Å, b = 7.13(1) Å, c = 12.47(1) Å, α = 95.1(1)°, β = 95.2(1)°, γ = 108.7(1)°, V = 466(2) Å3, Z = 4. Ziroite (ZrO2; IMA 2022-013) occurs as irregular crystals, ~1–4 μm in size, with baddeleyite, hibonite, and Ti,Al,Zr-oxide in corundum Grain 479-1a. Ziroite has an empirical formula (Zr0.72Ti4+0.26Mg0.02Al0.02Hf0.01)Σ1.03O2 and the tetragonal P42/nmc zirconia(HT)-type structure with the cell parameters: a = 3.60(1) Å, c = 5.18(1) Å, V = 67.1(3) Å3, Z = 2. Sassite (Ti3+2Ti4+O5; IMA 2022-014) occurs as subhedral-euhedral crystals, ~4–16 μm in size, with Ti,Al,Zr-oxide, mullite, osbornite, baddeleyite, alabandite, and glass in corundum Grain 1125C1. Sassite has an empirical formula (Ti3+1.35Al0.49Ti4+0.08Mg0.07)Σ1.99(Ti4+0.93Zr0.06Si0.01)Σ1.00O5 and the orthorhombic Cmcm pseudobrookite-type structure with the cell parameters: a = 3.80(1) Å, b = 9.85(1) Å, c = 9.99(1) Å, V = 374(1) Å3, Z = 4. Mizraite-(Ce) (Ce(Al11Mg)O19; IMA 2022-027) occurs as euhedral crystals, <1–14 μm in size, with Ce-silicate, Ti-sulfide, Ti,Al,Zr-oxide, ziroite, and thorianite in corundum Grain 198-8. Mizraite-(Ce) has an empirical formula (Ce0.76Ca0.10La0.07Nd0.01)Σ0.94(Al10.43Mg0.84Ti3+0.60Si0.09Zr0.04)Σ12.00O19 and the hexagonal P63/mmc magnetoplumbite-type structure with the cell parameters: a = 5.61(1) Å, c = 22.29(1) Å, V = 608(2) Å3, Z = 2. Yeite (TiSi; IMA 2022-079) occurs as irregular-subhedral crystals, 1.2–3.5 μm in size, along with wenjiite (Ti5Si3) and zhiqinite (TiSi2) in Ti-Si alloy inclusions in corundum Grain 198c. Yeite has an empirical formula (Ti0.995Mn0.003V0.001Cr0.001)(Si0.996P0.004) and the orthorhombic Pnma FeB-type structure with the cell parameters: a = 6.55(1) Å, b = 3.64(1) Å, c = 4.99(1) Å, V = 119.0(4) Å3, Z = 4. The five minerals are high-temperature oxide or alloy phases, formed in melt pockets in corundum xenocrysts derived from the upper mantle beneath Mt. Carmel.