TY - JOUR

T1 - NEW DATA ON Bi-, Pb-BEARING AND Mn-RICH GEM TOURMALINE FROM THE MALKHAN PEGMATITE DISTRICT (TRANSBAIKALIA)

AU - Верещагин, Олег Сергеевич

AU - Касаткин, Анатолий

AU - Škoda, Radek

PY - 2022/11

Y1 - 2022/11

N2 - Lead or/and Bi-bearing tourmalines are rare in nature while Mn-bearing ones are quite common. Here, we present new data on Bi- (up to ~2 wt % Bi2O3), Pb-bearing (up to ~2 wt % PbO) and Mn-rich (up to ~5 wt % MnO) tourmalines from the Irkutianka vein and Mn-rich tourmalines (up to ~6.5 wt % MnO) from the Novaya vein, both occurring at the Malkhan pegmatite district. Four gem-quality tourmalines (sm21-1, sm21-2, sm21-3, and sm21-4) of different color (yellow, colorless and red) and morphology (elongated and flattened) from the Irkutianka vein were studied by optical and scanning electron microscopy (SEM) and energydispersive analysis (EDS). Two samples (1015f and 1377f) of gemmy yellow tourmaline from the Novaya vein were additionally examined using WDS and LA-ICP-MS. All the studied tourmalines from the Irkutianka vein belong to fluor-elbaite – fluor-liddicoatite series and show the Na/Ca and Li/Mn/Fe zonation. The tourmalines from the Novaya vein, instead, do not show any zonation and belong to Mn-rich (up to 0.88 apfu Mn) fluor-elbaite. The complex chemical zonation observed for transitional metal contents resulted in the appearanceof color (or a lack of it). Colorless tourmaline sm21-4 has constant Bi impurity, whose amount decreases from the rim to the core (from 0.09 to 0.01 apfu) of the crystal in question. This tourmaline is among the Bi-richest species discovered so far. Lead was detected in rose to-colorless tourmaline sm21-3 and colorless one sm21-4. Only the inner parts of the tourmaline sm21-3 contain lead (<0.2 wt % PbO), while the Pb-richest domains (up to 30 mμ insize; Pb up to 0.09 apfu) were discovered in the core of the tourmaline sm21-4. We suppose that both Pb2+ and Bi3+ occupy the nine-coordinated X-site in the tourmaline crystal structure.

AB - Lead or/and Bi-bearing tourmalines are rare in nature while Mn-bearing ones are quite common. Here, we present new data on Bi- (up to ~2 wt % Bi2O3), Pb-bearing (up to ~2 wt % PbO) and Mn-rich (up to ~5 wt % MnO) tourmalines from the Irkutianka vein and Mn-rich tourmalines (up to ~6.5 wt % MnO) from the Novaya vein, both occurring at the Malkhan pegmatite district. Four gem-quality tourmalines (sm21-1, sm21-2, sm21-3, and sm21-4) of different color (yellow, colorless and red) and morphology (elongated and flattened) from the Irkutianka vein were studied by optical and scanning electron microscopy (SEM) and energydispersive analysis (EDS). Two samples (1015f and 1377f) of gemmy yellow tourmaline from the Novaya vein were additionally examined using WDS and LA-ICP-MS. All the studied tourmalines from the Irkutianka vein belong to fluor-elbaite – fluor-liddicoatite series and show the Na/Ca and Li/Mn/Fe zonation. The tourmalines from the Novaya vein, instead, do not show any zonation and belong to Mn-rich (up to 0.88 apfu Mn) fluor-elbaite. The complex chemical zonation observed for transitional metal contents resulted in the appearanceof color (or a lack of it). Colorless tourmaline sm21-4 has constant Bi impurity, whose amount decreases from the rim to the core (from 0.09 to 0.01 apfu) of the crystal in question. This tourmaline is among the Bi-richest species discovered so far. Lead was detected in rose to-colorless tourmaline sm21-3 and colorless one sm21-4. Only the inner parts of the tourmaline sm21-3 contain lead (<0.2 wt % PbO), while the Pb-richest domains (up to 30 mμ insize; Pb up to 0.09 apfu) were discovered in the core of the tourmaline sm21-4. We suppose that both Pb2+ and Bi3+ occupy the nine-coordinated X-site in the tourmaline crystal structure.

U2 - 10.31857/S0869605522060077

DO - 10.31857/S0869605522060077

M3 - Article

VL - CLI

SP - 1

EP - 13

JO - ЗАПИСКИ РОССИЙСКОГО МИНЕРАЛОГИЧЕСКОГО ОБЩЕСТВА

JF - ЗАПИСКИ РОССИЙСКОГО МИНЕРАЛОГИЧЕСКОГО ОБЩЕСТВА

SN - 0869-6055

IS - 6

ER -