Reference:
▪ Atencio, D., Andrade, M.B., Bindi, L., Bonazzi, P., Zoppi, M., Stanley, C.J., Kristiansen, R. (2018): Kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia. Mineralogical Magazine, 82, 1049-1055.
Abstract:
With the aim of defining the status of IMA-approved species for kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], the mineral occurring in the amazonite pegmatite from Ploskaya Mountain, Western Keivy Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia and previously studied from a structural point of view by Bindi et al. (2006) is here completely characterized. The mineral occurs in yellowish brown octahedral, cuboctahedral and massive crystals, up to 20 cm. Kenoplumbomicrolite has a white streak, a greasy lustre and is translucent. The Mohs hardness is about 6. The measurements of density (7.310–7.832 g/cm3) were affected by the ubiquitous presence of uraninite inclusions. Reflectance values were measured in air and using an immersion oil. Kenoplumbocrolite is optically isotropic. The empirical formula is (Pb1.300.30Ca0.29Na0.08U0.03)Σ2.00(Ta0.82Nb0.62Si0.23Sn4+0.15Ti0.07Fe3+0.10Al0.01)Σ2.00O6[0.52(OH)0.25O0.23]Σ1.00 (crystal used for the structural study), and (Pb1.330.66Mn0.01)Σ2.00(Ta0.87Nb0.72Sn4+0.18Fe3+0.11W0.08Ti0.04)Σ2.00O6[0.80(OH)0.10O0.10]Σ1.00 (average from additional fragments). The mineral is cubic, space group Fd3m. The unit cell parameters [a = 10.575(2) Å, V = 1182.6(8) Å3] refined from the X-ray powder diffraction data are in accord with those previously obtained from single crystal [a = 10.571(1) Å, V = 1181.3(2) Å3 and Z = 8]. The mineral description and its name have been approved by the IMA-CNMNC, under the number 2015-007a.
▪ Atencio, D., Andrade, M.B., Bindi, L., Bonazzi, P., Zoppi, M., Stanley, C.J., Kristiansen, R. (2018): Kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia. Mineralogical Magazine, 82, 1049-1055.
Abstract:
With the aim of defining the status of IMA-approved species for kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], the mineral occurring in the amazonite pegmatite from Ploskaya Mountain, Western Keivy Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia and previously studied from a structural point of view by Bindi et al. (2006) is here completely characterized. The mineral occurs in yellowish brown octahedral, cuboctahedral and massive crystals, up to 20 cm. Kenoplumbomicrolite has a white streak, a greasy lustre and is translucent. The Mohs hardness is about 6. The measurements of density (7.310–7.832 g/cm3) were affected by the ubiquitous presence of uraninite inclusions. Reflectance values were measured in air and using an immersion oil. Kenoplumbocrolite is optically isotropic. The empirical formula is (Pb1.300.30Ca0.29Na0.08U0.03)Σ2.00(Ta0.82Nb0.62Si0.23Sn4+0.15Ti0.07Fe3+0.10Al0.01)Σ2.00O6[0.52(OH)0.25O0.23]Σ1.00 (crystal used for the structural study), and (Pb1.330.66Mn0.01)Σ2.00(Ta0.87Nb0.72Sn4+0.18Fe3+0.11W0.08Ti0.04)Σ2.00O6[0.80(OH)0.10O0.10]Σ1.00 (average from additional fragments). The mineral is cubic, space group Fd3m. The unit cell parameters [a = 10.575(2) Å, V = 1182.6(8) Å3] refined from the X-ray powder diffraction data are in accord with those previously obtained from single crystal [a = 10.571(1) Å, V = 1181.3(2) Å3 and Z = 8]. The mineral description and its name have been approved by the IMA-CNMNC, under the number 2015-007a.