Avdeevite, a Na-Dominant Alkali Beryl: Determination as Valid Mineral Species and New Data

AGAKHANOV, A. A., D. A. STEPANENKO, N. V. ZUBKOVA, L. A. PAUTOV, I. V. PEKOV, A. V. KASATKIN, V. Yu. KARPENKO, V. A. AGAKHANOVA, Radek ŠKODA, S. N. BRITVIN a D. Yu. PUSHCHAROVSKY. Avdeevite, a Na-Dominant Alkali Beryl: Determination as Valid Mineral Species and New Data. Geology of Ore Deposits. Pleiades Publishing Inc, 2021, roč. 63, č. 7, s. 654-667. ISSN 1075-7015. Dostupné z: https://dx.doi.org/10.1134/S1075701521070023.

Základní údaje

• Originální název: Avdeevite, a Na-Dominant Alkali Beryl: Determination as Valid Mineral Species and New Data
• Autoři: AGAKHANOV, A. A. (garant), D. A. STEPANENKO, N. V. ZUBKOVA, L. A. PAUTOV, I. V. PEKOV, A. V. KASATKIN, V. Yu. KARPENKO, V. A. AGAKHANOVA, Radek ŠKODA (203 Česká republika, domácí), S. N. BRITVIN a D. Yu. PUSHCHAROVSKY.
• Vydání: Geology of Ore Deposits, Pleiades Publishing Inc, 2021, 1075-7015.

Další údaje

• Originální jazyk: angličtina
• Typ výsledku: Článek v odborném periodiku
• Obor: 10504 Mineralogy
• Stát vydavatele: Spojené státy
• Utajení: není předmětem státního či obchodního tajemství
• WWW: URL
• Impakt faktor: Impact factor: 0.679
• Kód RIV: RIV/00216224:14310/21:00124535
• Organizační jednotka: Přírodovědecká fakulta
• Doi: http://dx.doi.org/10.1134/S1075701521070023
• UT WoS: 000758871100003
• Klíčová slova anglicky: avdeevite; new mineral; alkali beryl; beryl group; crystal structure; granitic pegmatite; Kat Chay; Momeik; Myanmar
• Štítky: rivok
• Příznaky: Mezinárodní význam, Recenzováno

Anotace

This paper describes the first Na-dominant member of the beryl group, named avdeevite. The sample, which became its holotype, was found in a granitic pegmatite at the Kat Chay (Palelni) mine near the town of Momeik, Kyaukme district, Shan State, Myanmar. Both avdeevite and beryl form sheaflike aggregates up to 4 cm, consisting of hexagonal prismatic crystals up to 1 сm long and up to 1 mm thick. These crystals consist of epitactically intergrown avdeevite (core) and beryl (rim). The new mineral is pink and transparent with vitreous luster. The Mohs hardness is 8, Dmeas = 2.89(2) and Dcalc = 2.875 g/cm3. Avdeevite is optically uniaxial (–), ω = 1.601(2), ε = 1.594(2); in transmitted light, the mineral is colorless and nonpleochroic. The chemical composition of holotype (electron microprobe, Be, Li and H by ion microprobe) is, wt %: 61.06 SiO2, 17.40 Al2O3, 8.58 BeO, 1.77 Na2O, 0.09 K2O, 6.44 Cs2O, 1.38 Rb2O, 2.51 Li2O, 0.42 H2O; the total is 99.63. The empirical formula is (Na0.34Cs0.27H2O0.14Rb0.09K0.01)Σ0.85(Be2.04Li1.00)Σ3.04Al2.03Si6.03O18. Taking into account the previously published data for samples with compositions corresponding to avdeevite, the simplified formula of this mineral may be most correctly written as: [(Na,R')0.5–1(H2O)y]{(Be,Li)3(Al,M2+)2Si6O18}, y ≤ 1, R' = Cs, Rb, K, Ca, M2+ = Fe, Mg, Mn. The crystal structure has been studied by single-crystal X-ray diffraction, R = 0.0322. The mineral is hexagonal, space group P6/mcc. The unit-cell parameters are: a = 9.2287(4) Å, c = 9.2610(3) Å, V = 683.07(5) Å3, and Z = 2. The strongest reflections of the XRD pattern are [dmeas, Å (I, %) (hkl)]: 7.96 (82) (100), 4.60 (31) (002), 3.99 (102) (200), 3.26 (100) (112), 3.02 (37) (202) (210), 2.866 (84) (211), 1.742 (19) (304) (410). Avdeevite belongs to the beryl structural type. This mineral differs from beryl sensu stricto in that the total large cations in channels exceeds 0.5 apfu and Na dominates among these cations. Avdeevite is named after Ivan Vasil’evich Avdeev (1818–1865), the renowned Russian chemist and mining engineer, who led the major studies of natural and synthetic beryllium compounds. The paper also contains data on the history of Na-bearing beryls including previously described samples, which correspond to avdeevite.