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A new Sn-rich garnet, toturite Ca3Sn2Fe2SiO12, occurs as an accessory mineral in high-temperature altered carbonate-silicate xenoliths in ignimbrite of the Upper Chegem structure in the Northern Caucasus, Kabardino-Balkaria, Russia. The empirical formula of toturite from the holotype sample is (Ca2.989Fe0.0112+)Σ3(Sn1.4634+Sb0.3255+Ti0.1934+Zr0.013Mg0.003Nb0.0025+Cr0.001)Σ2(Fe1.6333+Al0.609Si0.552Ti0.1664+Fe0.0392+V0.0015+)Σ3O12. The mineral forms thin regular growth zones and irregular spots in the Fe3+-dominant analog of kimzeyite. Toturite is cubic, Ia3̄d, a ≈ 12.55 Å, as is confirmed by electron backscatter diffraction (EBSD) data. The strongest lines of the calculated powder diffraction pattern are [d, Å (hkl) I]: 2.562 (422) 100, 1.677 (642) 91, 3.138 (400) 74, 4.437 (220) 67, 1.146 (10.4.2) 31, 1.046 (884) 25, 1.984 (620) 23. Raman spectra of toturite are analogous to those of kimzeyite and shows the following diagnostic bands (cm-1): 244, 301, 494, 497, 575, 734. The association of toturite with larnite, rondorfite, wadalite, magnesioferrite, lakargiite, and cuspidine indicates a high temperature (>800 °C) of formation. The mineral name is given after the Totur River situated in Eltyubyu village, also Totur is the name of a Balkarian god. [ABSTRACT FROM AUTHOR]

Two new antimonian garnets--bitikleite-(SnAl) Ca3SbSnAl3O12 and bitikleite-(ZrFe) Ca3SbZrFe3O12--have been found as accessory minerals in the cuspidine zone of high-temperature skarns in a carbonate-silicate xenolith at the contact with ignimbrites within the Upper Chegem structure in the Northern Caucasus, Kabardino-Balkaria, Russia. The bitikleite series forms a solid solution with garnets of the kimzeyite-schorlomite and toturite type. Antimony-garnets form crystals up to 50 µm across containing kimzeyite cores and thin subsequent zones of complex lakargiite-tazheranite-kimzeyite pseudomorphs after zircon. Bitikleite-(SnAl) has a = 12.5240(2) Å, V = 1964.40(3) ų and bitikleite-(ZrFe) has a = 12.49 Å, V = 1948.4 ų (Ia3̅d, Z = 8). The strongest powder diffraction lines of bitikleite-(SnAl) are [d, Å (hkl)]: 4.407 (220), 3.118 (440), 2.789 (420), 2.546 (422), 1.973 (620), 1.732 (640), 1.668 (642), and 1.396 (840). The strongest calculated powder diffraction lines of bitikleite-(ZrFe) are [d, Å (hkl)]: 4.416 (220), 3.123 (440), 2.793 (420), 2.550 (422), 1.975 (620), 1.732 (640), 1.669 (642), and 1.396 (840). The Raman spectra of bitikleite garnets are similar to the spectra of kimzeyite and toturite. Larnite, rondorfite, wadalite, magnesioferrite, tazheranite, lakargiite, kimzeyite, and toturite associated with bitikleite garnets are typical of high-temperature (>800 °C) formation. [ABSTRACT FROM AUTHOR]