Record details

    Oxy-schorl, Na(Fe2+2Al)Al6Si6O18(BO3)3(OH)3O, a new mineral from Zlatá Idka, Slovak Republic and Přibyslavice, Czech Republic
    Bačík, P.
    Breiter, Karel
    Cempírek, J.
    Ďuďa, R.
    Filip, J.
    Groat, L. A.
    Klementová, Mariana
    Novák, M.
    Ozdín, D.
    Škoda, R.
    Uher, P.
Publication type
    článek v odborném periodiku
Source title - serial
    American Mineralogist
    Roč. 98, 2/3
    s. 485-492
    Rozsah: 8 s. : P
Subject category
    crystal-structure refinement
    electron microanalysis
    new mineral
    tourmaline-supergroup minerals
    Zlatá Idka
Abstract (in english)
   Oxy-schorl, Na(Fe2+2Al)Al6Si6O18(BO3)3(OH)3O, is a new mineral species of the tourmaline group and it was found on two localities - Přibyslavice, Czech Republic and co-type locality Zlatá Idka, Slovak Republic. Oxy-schorl from Přibyslavice occurs in a foliated muscovite-tourmaline orthogneiss with associated minerals including K-feldspar (orthoclase-perthite), albite, quartz, muscovite, biotite, apatite and garnet. Oxy-schorl from Zlatá Idka occurs in extensively metasomatically altered Silurian metarhyolite pyroclastics with muscovite, quartz, and albite. Oxy-schorl from Přibyslavice forms abundant brownish black subhedral, columnar crystals, up to 1 cm in size, arranged in thin layers, or irregular clusters up to 5 cm in diameter in muscovite-tourmaline orthogneiss. Oxy-schorl from Zlatá Idka forms fan-shaped aggregates of greenish black acicular crystals ranging up to 2 cm in size, with aggregates up to 3.5 cm across.
   Oxy-schorl has a brown (Přibyslavice) to pale grey (Zlatá Idka) streak. Oxy-schorl from both localities is brittle and has a Mohs hardness of ca 7. It has no observable cleavage and parting. Oxy-schorl has a measured density of 3.19 g/cm (Přibyslavice) and 3.17 g/cm (Zlatá Idka) using pycnometry and calculated density of 3.198 g/cm (Přibyslavice), 3.208 g/cm (Zlatá Idka) using empirical formulae and separate unit cell data. In plane polarized light, it is pleochroic, O = dark greyish-green (Přibyslavice) and green to bluish-green (Zlatá Idka), E = pale brown (Přibyslavice) and pale yellowish to nearly colorless (Zlatá Idka). Oxy-schorl is uniaxial negative. Oxy-schorl is trigonal, space group R3m, a = 15.9853(12) Å, c = 7.1538(6) Å, V = 1583.1(2) Å3, Z = 3.
    AV ČR Brno, Geologický ústav
Contributor code
    AV ČR, GLÚ
Source format
Import date
    23. 10. 2014