Podrobnosti záznamu

Název
    ZACCARINIITE, RhNiAs, A NEW PLATINUM-GROUP MINERAL SPECIES FROM LOMA PEGUERA, DOMINICAN REPUBLIC
Autor
    Baker, Ronald
    Bermejo, Raul
    Drábek, Milan
    Garuti, Giorgio
    Laufek, František
    Longo, Francisco
    Proenza, Joa
    Stanley, Chris
    Thalhammer, Oscar
    Vymazalová, Anna
Jazyk
    anglicky
Typ dokumentu
    článek v periodiku
Zdrojový dokument - seriál
    Canadian Mineralogist
Svazek/č.
    Roč. 50, č. 5
Strany
    9
Rok
    2012
Výraz tezauru
    zaccariniite, platinum-group mineral, Rh-Ni arsenide, electron-microprobe data, reflectance data, synthetic RhNiAs, X-ray-diffraction data, Cu2Sb, crystal structure, Loma Peguera, Dominican Republic
Klíčové slovo
    DOMINICAN
    LOMA
    MINERAL
    NEW
    PEGUERA
    PLATINUM-GROUP
    REPUBLIC
    RhNiAs
    SPECIES
    ZACCARINIITE
Abstrakt (anglicky)
   Zaccariniite, RhNiAs, is a new platinum-group mineral discovered in the Loma Peguera ophiolitic chromitite, Dominican Republic. The new mineral forms anhedral grains (1-20 ?m in size) and occurs intergrown with garutiite, in association with hexaferrum, Ru-Os-Ir-Fe alloys, Ru-Os-Ir-Fe oxygenated compounds, and chromite. Zaccariniite is opaque, has a metallic lustre and a grey streak. The mineral is brittle, with no cleavage. Values of VHN5 (10 indentations on different grains of synthetic RhNiAs) fall between 166 and 286 kg/mm2, with a mean value of 218 kg/mm2, corresponding to a Mohs hardness of approximately 3 1/2 -4. Under plane-polarized reflected light, the mineral is white with brownish to pinkish tints, has moderate to strong bireflectance, a strong white to pinkish brownish white pleochroism, and strong anisotropy, with rotation tints from orange to blue-green; it exhibits no internal reflections. Reflectance values of zaccariniite in air (R1, R2 in %) are: 49.4, 49.4 at 470 nm
   , 52.4, 53.2 at 546 nm, 54.2, 53.2 at 589 nm, and 56.6, 53.3 at 650 nm. Three electron-microprobe analyses of natural zaccariniite gave an average composition of: Rh 41.77, Os 0.51, Ir 0.64, Ru 0.46, Pd 0.34, Ni 23.75, Fe 0.53, As 27.84, S 0.10, for a total of 96.09 wt.%, corresponding to the empirical formula (Rh1.01Os0.01Ir0.01Ru0.01Pd0.01)?1.05(Ni1.00Fe0.02)?1.02(As0.92S0.01)?0.93 based on three atoms. The average result of twenty-eight analyses of synthetic zaccariniite is: Rh 44.57, Ni 24.50, and As 31.82 total 100.88 wt.%, corresponding to Rh1.02Ni0.98As1.00. The mineral is tetragonal, belongs to space group P4/nmm with lattice parameters a = 3.5498(1), c = 6.1573(2) A, V = 77.59(1) A3, Z = 2, and crystallizes with the Cu2Sb structure type. The new Rh-Ni arsenide is named after the Federica Zaccarini in recognition of her important contribution to the mineralogy of platinum-group elements.
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (RIV)
Zdrojový formát
    R
Datum importu
    15. 10. 2014