Redefinition of beraunite, Fe3C6 (PO4)4O(OH)4 6H2O, and discreditation of the name eleonorite: a re-investigation of type material from the Hrbek Mine (Czech Republic)

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F22%3A00000187" target="_blank" >RIV/00025798:_____/22:00000187 - isvavai.cz</a>

Result on the web

<a href="https://ejm.copernicus.org/articles/34/223/2022/" target="_blank" >https://ejm.copernicus.org/articles/34/223/2022/</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/ejm-34-223-2022" target="_blank" >10.5194/ejm-34-223-2022</a>

Result language

angličtina

Original language name

Redefinition of beraunite, Fe3C6 (PO4)4O(OH)4 6H2O, and discreditation of the name eleonorite: a re-investigation of type material from the Hrbek Mine (Czech Republic)

Original language description

Re-investigation of the type material of beraunite from the Hrbek Mine, Svatá Dobrotivá, CzechRepublic, proved the identity of beraunite and eleonorite. Based on this study, the mineral eleonoritewas discredited, and the ideal formula of beraunite was redefined from Fe2CFe3C5 (PO4)4(OH)5 6H2O toFe3C6 (PO4)4O(OH)4 6H2O. Beraunite from Hrbek Mine usually forms prismatic crystals flattened on {100};elongated along b axis, striated on {100} jj b, up to 0.2 0.53 mm, often in radial clusters up to 6mmin size in association with black goethite, olive-green to dark green dufrénite and yellow to orange cacoxenite.Beraunite is hyacinth red, dark red, or red-brown and has a light orange-red streak; crystals aretranslucent,with a vitreous luster. The symmetry of the structure was found to be lower (Cc) than reportedin the past (C2=c); this has been proven by the crystal structure refinement, Robs D2.7percent for Cc and 8percent for C2=m. Refined unit-cell parameters obtained from powder X-ray diffraction data of the originalmaterial of Friedrich August Breithaupt are a D 20.653(2), b D5.1433(6), c D19.241(2) angstroem, D93.560(9),and V D2039.9(2)angstroem3. Calculated density is 2.961 g cm3. Beraunite is optically biaxial (C), D1.768(2), D1.781(3), >1:805, 2Vmeas D69(4), and 2Vcalc is not possible to calculate. Dispersion of optical axes isstrong, r>v. The orientation is Y D b, X a, and Z c. Pleochroism is strong; Z (brown-red) Y>X (bothbrownish yellow). The empirical formula of the original beraunite sample calculated on the basis of PD4 apfuis (Fe3C5:76Al0:15Zn0:01)5:92(PO4)4:00O0:99(OH)3:77 6H2O. The 57Fe Mössbauer spectrum of beraunite neotype(National Museum, Prague) from type locality implies that all iron atoms in beraunite structure are exclusivelytrivalent, located at the M site with different next-nearest-neighbor configurations. There is no spectral evidencefor Fe2C or iron in some impurities (e.g., limonite).

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10504 - Mineralogy

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

European Journal of Mineralogy

ISSN

0935-1221

e-ISSN

—

Volume of the periodical

34

Issue of the periodical within the volume

2

Country of publishing house

DE - GERMANY

Number of pages

16

Pages from-to

223-238

UT code for WoS article

000780842500001

EID of the result in the Scopus database

2-s2.0-85125195079