TY - JOUR

T1 - Vittinkiite, MnMn4[Si5O15], a member of the rhodonite group with a long history: definition as a mineral species

AU - Shchipalkina, Nadezhda V.

AU - Pekov, Igor V.

AU - Chukanov, Nikita V.

AU - Zubkova, Natalia V.

AU - Belakovskiy, Dmitry I.

AU - Britvin, Sergey N.

AU - Koshlyakova, Natalia N.

PY - 2020/12

Y1 - 2020/12

N2 - The rhodonite-group mineral with the idealised, end-member formula MnMn 4 [Si 5 O 15 ] and the crystal chemical formula VII M (5) Mn VI M (1–3) Mn 3 VII M (4) Mn[Si 5 O 15 ] (Roman numerals indicate coordination numbers) is defined as a valid mineral species named vittinkiite after the type locality Vittinki (Vittinge) mines, Isokyrö, Western and Inner Finland Region, Finland. Vittinkiite is an isostructural analogue of rhodonite, ideally CaMn 4 [Si 5 O 15 ], with Mn 2+ > Ca at the M (5) site. Besides Vittinki, vitiinkiite was found in more than a dozen rhodonite deposits worldwide, however, it is significantly less common in comparison with rhodonite. The mineral typically forms pink to light pink massive, granular aggregates and is associated with quartz, rhodonite, tephroite, pyroxmangite and Mn oxides. Vittinkiite is optically biaxial (+), with α = 1.725(4), β = 1.733(4), γ = 1.745(5) and 2V meas = 75(10)° (589 nm). The chemical composition of the holotype (wt.%, electron microprobe) is: MgO 0.52, CaO, 0.93, MnO 51.82, FeO 1.26, ZnO 0.11, SiO 2 46.48, total 101.12. The empirical formula calculated based on 15 O apfu is Mn 4.71 Ca 0.11 Fe 0.11 Mg 0.08 Zn 0.01 Si 4.99 O 15 . Vittinkiite is triclinic, space group P $\bar{1}$ , with a = 6.6980(3), b = 7.6203(3), c = 11.8473(5) Å, α = 105.663(3), β = 92.400(3), γ = 94.309(3)°, V = 579.38(7) Å 3 and Z = 2. The crystal structure is solved on a single crystal to R 1 = 3.85%. Polymorphism of MnSiO 3 (rhodonite-, pyroxmangite-, garnet- and clinopyroxene-type manganese metasilicates) is discussed, as well as the relationship between vittinkiite and pyroxmangite, ideally Mn 7 [Si 7 O 21 ], and the application of infrared spectroscopy for the identification of manganese pyroxenoids.

AB - The rhodonite-group mineral with the idealised, end-member formula MnMn 4 [Si 5 O 15 ] and the crystal chemical formula VII M (5) Mn VI M (1–3) Mn 3 VII M (4) Mn[Si 5 O 15 ] (Roman numerals indicate coordination numbers) is defined as a valid mineral species named vittinkiite after the type locality Vittinki (Vittinge) mines, Isokyrö, Western and Inner Finland Region, Finland. Vittinkiite is an isostructural analogue of rhodonite, ideally CaMn 4 [Si 5 O 15 ], with Mn 2+ > Ca at the M (5) site. Besides Vittinki, vitiinkiite was found in more than a dozen rhodonite deposits worldwide, however, it is significantly less common in comparison with rhodonite. The mineral typically forms pink to light pink massive, granular aggregates and is associated with quartz, rhodonite, tephroite, pyroxmangite and Mn oxides. Vittinkiite is optically biaxial (+), with α = 1.725(4), β = 1.733(4), γ = 1.745(5) and 2V meas = 75(10)° (589 nm). The chemical composition of the holotype (wt.%, electron microprobe) is: MgO 0.52, CaO, 0.93, MnO 51.82, FeO 1.26, ZnO 0.11, SiO 2 46.48, total 101.12. The empirical formula calculated based on 15 O apfu is Mn 4.71 Ca 0.11 Fe 0.11 Mg 0.08 Zn 0.01 Si 4.99 O 15 . Vittinkiite is triclinic, space group P $\bar{1}$ , with a = 6.6980(3), b = 7.6203(3), c = 11.8473(5) Å, α = 105.663(3), β = 92.400(3), γ = 94.309(3)°, V = 579.38(7) Å 3 and Z = 2. The crystal structure is solved on a single crystal to R 1 = 3.85%. Polymorphism of MnSiO 3 (rhodonite-, pyroxmangite-, garnet- and clinopyroxene-type manganese metasilicates) is discussed, as well as the relationship between vittinkiite and pyroxmangite, ideally Mn 7 [Si 7 O 21 ], and the application of infrared spectroscopy for the identification of manganese pyroxenoids.

UR - https://www.mendeley.com/catalogue/3b0f0075-d769-3fc4-875b-ac855ea24d7e/

U2 - 10.1180/mgm.2020.75

DO - 10.1180/mgm.2020.75

M3 - Article

VL - 84

SP - 869

EP - 880

JO - Mineralogical Magazine

JF - Mineralogical Magazine

SN - 0026-461X

IS - 6

ER -