Hechtsbergite, Bi₂O(OH)(VO₄), a new mineral from the Black Forrest, Germany

Autor(en)

Werner Krause, Heinz-Jürgen Bernhardt, Günter Blaß, Herta Silvia Effenberger, Hans-Werner Graf

Abstrakt

Hechtsbergite is assocd. with eulytite, namibite, chrysocolla, bismutite, beyerite, and mixite on samples from the Hechtsberg quarry near Hausach, Black Forest, Germany. The mineral forms aggregates and idiomorphic crystals up to a diam. of 0.2 mm. No distinct cleavage was obsd., the fracture is conchoidal and the Mohs' hardness is 4.5. Hechtsbergite has a brown color with an adamantine luster; the streak is yellow. The crystals are biaxial pos., 2V = 50(5)°, nx = 2.26(2), ny = 2.27 (calc.), nz = 2.30(2); X II b and Z L c .apprx. 35° (in the obtuse of beta). The most prominent crystallog. form of the monoclinic holohedral crystals is {111}; addnl. forms are {112}, {113}, {.hivin.101}, {.hivin.102}, and {.hivin.302}. Electron-microprobe investigations give Bi2O3 83.02, V2O5 15.18, As2O5 0.52, H2O (calc.) 1.59, sum 100.31 wt.-%. The empirical formula based on 6 oxygen atoms is Bi2.03O1.08(OH)1.01(VO4)0.95(AsO4)0.03, or idealized Bi2O(OH)(VO4). The 5 strongest lines of the powder diffraction pattern are [dhkl in .ANG., (Iobs) (hkl)]: 4.279 (41) (012), 3.267 (100+) (120, 20.hivin.2, 12.hivin.1, 112), 3.150 (63) (013), 2.734 (35) (211), 2.036 (29) (13.hivin.3, 23.hivin.1, 213, 033). Hechtsbergite has the space group P21/c, a = 6.791(1), b = 7.535(1), c = 10.881(1) .ANG., beta = 107.00(1)°, V = 546.6 .ANG.3, Z = 4, Dx = 6.87 g/cm3. As confirmed by the Rietveld refinement of the x-ray powder diffraction pattern, hechtsbergite is the vanadium analog of atelestite; for smrkovecite isotypy is taken for granted. The name is for the locality.

Organisation(en)

Institut für Mineralogie und Kristallographie

Externe Organisation(en)

Ruhr-Universität Bochum (RUB)

Journal

Neues Jahrbuch für Mineralogie. Monatshefte

Band

1997

Seiten

271-287

Anzahl der Seiten

17

ISSN

0028-3649

Publikationsdatum

1997

Peer-reviewed

Ja

ÖFOS 2012

105113 Kristallographie, 105116 Mineralogie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/30d01c78-dda2-494b-98bf-c1a585237fbd