TY - JOUR

T1 - JANCHEVITE, Pb7V(O8.5vac0.5)Cl2, A NEW MINERAL FROM THE KOMBAT MINE, NAMIBIA

AU - Chukanov, N.V.

AU - Nekrasova, D.O.

AU - Siidra, O.I.

AU - Polekhovsky, Y.S.

AU - Pekov, I.V.

PY - 2018/3/31

Y1 - 2018/3/31

N2 - The new mineral janchevite was discovered in Mn-oxide ore from the Kombat mine, Grootfontein district, Otjozondjupa region, Namibia. Associated minerals are baryte, hausmannite, calcite, magnesite, and kombatite. Janchevite forms orange-red thick tabular anhedral to subhedral grains up to 0.4×0.8×0.8 mm in size. The luster is adamantine. The mineral is brittle, with Mohs' hardness of 2. Distinct cleavage on {001} is observed. D calc = 8.16 g/cm 3. The reflectance values [R max/R min, % (λ, nm)] are: 20.56/20.06 (470), 19.20/18.81 (546), 19.06/18.59 (589), 19.31/18.85 (650). An infrared spectrum indicates the absence of H-bearing groups and indicates V and Mo valences of 5+ and 6+, respectively. The chemical composition is (electron microprobe, wt.%): PbO 91.64, SiO 2 0.45, V 2O 5 1.95, MoO 3 2.41, Cl 4.16, -O=Cl .0.94, total 99.67. The empirical formula based on (Pb+V+Mo+Si)=8 apfu is Pb 7.20V 5+ 0.38Mo 6+ 0.29Si 0.13Cl 2.06O 8.25. Janchevite is the V-dominant analogue of parkinsonite. The mineral is tetragonal and its unit-cell parameters as determined from single-crystal X-ray diffraction data are: a 3.9591(5), c 22.6897(3) Å, V 355.65(1) Å 3; Z=1. Powder X-ray diffraction data conform to the space group I4/mmm; the strongest lines of the PXRD pattern [d, Å (I/I0, %) (hkl)] are: 3.889 (24) (011), 3.501 (31) (013), 2.979 (86) (015), 2.833 (25) (008), 2.794 (100) (110), 1.992 (26) (118), 1.988 (49) (020), 1.649 (46) (215). Janchevite is named in honor of the prominent Macedonian mineralogist Prof. Dr. Simeon Janchev (b. 1942).

AB - The new mineral janchevite was discovered in Mn-oxide ore from the Kombat mine, Grootfontein district, Otjozondjupa region, Namibia. Associated minerals are baryte, hausmannite, calcite, magnesite, and kombatite. Janchevite forms orange-red thick tabular anhedral to subhedral grains up to 0.4×0.8×0.8 mm in size. The luster is adamantine. The mineral is brittle, with Mohs' hardness of 2. Distinct cleavage on {001} is observed. D calc = 8.16 g/cm 3. The reflectance values [R max/R min, % (λ, nm)] are: 20.56/20.06 (470), 19.20/18.81 (546), 19.06/18.59 (589), 19.31/18.85 (650). An infrared spectrum indicates the absence of H-bearing groups and indicates V and Mo valences of 5+ and 6+, respectively. The chemical composition is (electron microprobe, wt.%): PbO 91.64, SiO 2 0.45, V 2O 5 1.95, MoO 3 2.41, Cl 4.16, -O=Cl .0.94, total 99.67. The empirical formula based on (Pb+V+Mo+Si)=8 apfu is Pb 7.20V 5+ 0.38Mo 6+ 0.29Si 0.13Cl 2.06O 8.25. Janchevite is the V-dominant analogue of parkinsonite. The mineral is tetragonal and its unit-cell parameters as determined from single-crystal X-ray diffraction data are: a 3.9591(5), c 22.6897(3) Å, V 355.65(1) Å 3; Z=1. Powder X-ray diffraction data conform to the space group I4/mmm; the strongest lines of the PXRD pattern [d, Å (I/I0, %) (hkl)] are: 3.889 (24) (011), 3.501 (31) (013), 2.979 (86) (015), 2.833 (25) (008), 2.794 (100) (110), 1.992 (26) (118), 1.988 (49) (020), 1.649 (46) (215). Janchevite is named in honor of the prominent Macedonian mineralogist Prof. Dr. Simeon Janchev (b. 1942).

KW - Janchevite

KW - Kombat mine

KW - Lead vanadate oxychloride

KW - Namibia

KW - New mineral

KW - ANALOG

KW - lead vanadate oxychloride

KW - CRYSTAL-STRUCTURE

KW - PB OXYCHLORIDE MINERALS

KW - new mineral

KW - janchevite

KW - PARKINSONITE

KW - SAHLINITE

KW - CHEMISTRY

KW - ASISITE

UR - http://www.scopus.com/inward/record.url?scp=85054175761&partnerID=8YFLogxK

UR - http://www.canmin.org/lookup/doi/10.3749/canmin.1700081

UR - http://www.mendeley.com/research/janchevite-pb-sub7sub-v-sup5sup-o-sub85sub-sub05sub-cl-sub2sub-new-mineral-kombat-mine-namibia

U2 - 10.3749/canmin.1700081

DO - 10.3749/canmin.1700081

M3 - Article

VL - 56

SP - 159

EP - 165

JO - Canadian Mineralogist

JF - Canadian Mineralogist

SN - 0008-4476

IS - 2

ER -