Dachiardite-K, (K2Ca)(Al4Si20O48) · 13H2O, a new zeolite from Eastern Rhodopes, Bulgaria
| Autor: | Dmitriy I. Belakovskiy, S. Encheva, Igor V. Pekov, Sergey N. Britvin, P. Petrov, Nikita V. Chukanov, Sergey M. Aksenov |
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| Rok vydání: | 2016 |
| Předmět: |
Acicular
Chalcedony Geology Cleavage (crystal) 02 engineering and technology Electron microprobe engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Mordenite 0104 chemical sciences Crystallography Geochemistry and Petrology engineering Celadonite Economic Geology 0210 nano-technology Chemical composition Monoclinic crystal system |
| Zdroj: | Geology of Ore Deposits. 58:666-673 |
| ISSN: | 1555-6476 1075-7015 |
| DOI: | 10.1134/s1075701516080079 |
| Popis: | Dachiardite-K (IMA No. 2015-041), a new zeolite, is a K-dominant member of the dachiardite series with the idealized formula (К2Са)(Al4Si20O48) · 13H2О. It occurs in the walls of opal–chalcedony veinlets cutting hydrothermally altered effusive rocks of the Zvezdel paleovolcanic complex near the village of Austa, Momchilgrad Municipality, Eastern Rhodopes, Bulgaria. Chalcedony, opal, dachiardite-Ca, dachiardite-Na, ferrierite-Mg, ferrierite-K, clinoptilolite-Ca, clinoptilolite-K, mordenite, smectite, celadonite, calcite, and barite are associated minerals. The mineral forms radiated aggregates up to 8 mm in diameter consisting of split acicular individuals. Dachiardite-K is white to colorless. Perfect cleavage is observed on (100). D meas = 2.18(2), D calc = 2.169 g/cm3. The IR spectrum is given. Dachiardite-K is biaxial (+), α = 1.477 (calc), β = 1.478(2), γ = 1.481(2), 2V meas = 65(10)°. The chemical composition (electron microprobe, mean of six point analyses, H2O determined by gravimetric method) is as follows, wt %: 4.51 K2O, 3.27 CaO, 0.41 BaO, 10.36 A12O3, 67.90 SiO2, 13.2 H2O, total is 99.65. The empirical formula is H26.23K1.71Ca1.04Ba0.05Al3.64Si20.24O61. The strongest reflections in the powder X-ray diffraction pattern [d, A (I, %) (hkl)] are: 9.76 (24) (001), 8.85 (58) (200), 4.870 (59) (002), 3.807 (16) (202), 3.768 (20) (112, 020), 3.457 (100) (220), 2.966 (17) (602). Dachiardite-K is monoclinic, space gr. C2/m, Cm or C2; the unit cell parameters refined from the powder X-ray diffraction data are: a = 18.670(8), b = 7.511(3), c = 10.231(4) A, β = 107.79(3)°, V= 1366(1) A3, Z = 1. The type specimen has been deposited in the Earth and Man National Museum, Sofia, Bulgaria, with the registration number 23927. |
| Databáze: | OpenAIRE |
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