Record details

    Parascorodite, FeAsO4.2H2O - a new mineral from Kaňk near Kutná Hora, Czech Republic
Statement of responsibility
    Petr Ondruš, Roman Skála, Cecilia Viti, František Veselovský, František Novák, Jiří Jansa
    Jansa, Jiří
    Novák, František
    Ondruš, Petr
    Skála, Roman
    Veselovský, František
    Viti, Cecilia
Source title - serial
    American mineralogist
    Vol. 84, no. 9
    p. 1439-1444
    2 obr., 5 fot., 3 tab., 8 bibl.
    Zkr. název ser.: Amer. Mineralogist
Subject group
    analýza termická
    difrakce rentgenová
    mikroskopie elektronová transmisní
    mineralogie topografická
    minerály supergenní
    nový minerál
    spektrometrie IR
Geographical name
    Jáchymov (Karlovy Vary)
    Kaňk (Kutná Hora)
Abstract (in english)
   Parascorodite, a new mineral from Kaňk near Kutná Hora, Central Bohemia, Czech Republic, forms earthy white to white-yellow aggregates associated with scorodite, pitticite, bukovskýite, kaňkite, zýkaite, gypsum, and jarosite, wet chemical analysis gave (in wt. perc.): As2O5 44.45, P2O5 0.84, SO3 1.53, Fe2O3 34.55, Al2O3 0.17, H2O 17.81, totaling 99.95. The simplified chemical formula is FeAsO4.2H2O. Selected area electron diffraction suggests hexagonal or trigonal symmetry. The extinction symbol is P-c-. Powder X-ray diffraction yielded unit-cell parameters a=8.9327(5)A, c=9.9391(8)A, V=686.83(8)A3, Z=6. Densities (measured and calculated, respectively) are Dm=3.213(3) g/cm3 and Dx=3.212 g/cm3. SEM and TEM images showed that basal sections of parascorodite are hexagonal in shape; thicker prismatic crystals were also observed. Crystal size varies between 0.1 to 0.5um.
   The strongest lines in the X-ray powder diffraction patternare [d[I](hkl)]: 4.184(44)(012), 4.076(100)(111), 3.053(67)(202), 2.806(68)(211), 2.661(59)(113), 2.520(54)(212), 2.2891(44)(032). Refractive indexes could nothave been measured due to extremely small crystallite size, n(calc) = 1.797. The TG curve shows two weight losses: at 20-150 °C (2.1 wt. perc., absorbed water) and at 150-620 °C (15.5 wt. perc., molecular water) respectively. They correspond to the endothermic peaks on the DTA curve at 120 and 260 °C. Strong exothermic reaction observed at 585 °C reflects formation of the phase FeAsO4. Infrared absorption spectra of parascorodite are close to those of scorodite
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
Entered date
    16. 4. 2008
Import date
    8. 8. 2012