- 著者
- Tohru OZAWA Akihiro SAITOW Hidemichi HORI
- 出版者
- Japan Association of Mineralogical Sciences
- 雑誌
- Mineralogical Journal (ISSN:05442540)
- 巻号頁・発行日
- vol.20, no.4, pp.179-187, 1998 (Released:2007-03-31)
- 参考文献数
- 14
- 被引用文献数
- 1 1
Giessenite was reported as an acicular crystal that shared a close association with Sb-bearing cosalite from the Otome mine, Yamanashi Prefecture (Ozawa and Hori, 1982). Recent criteria classify it as izoklakeite.The Otome izoklakeite, which is orthorhombic (Pnnm or Pnn2 from its orthogonal lattice and systematic extinction, in agreement with previous reports), has unit-cell dimensions of a 34.067, b 38.085, c 4.056Å. In addition, diffuse reflections which double the periodicity of 4.056Å along the c-axis are observed, also in agreement with the report on Vena izoklakeite (Zakrzewski and Makovicky, 1986).An electron microprobe analysis gives Cu 0.8, Fe 0.3, Ag 1.1, Pb 46.5, Bi 27.2, Sb 7.3, S 16.2, total 99.4wt.%, yielding the empirical formula (Cu2.7Fe1.2)3.9Ag2.2Pb48.7(Bi28.2Sb13.0)41.2S109.7, assuming the total cation=96 in a unit cell. It has a Sb/(Sb+Bi) value of 0.316, and is the most Bi-rich of the known izoklakeites.
- 著者
- Massimo NESPOLO Tohru OZAWA Yusuke KAWASAKI Kazumasa SUGIYAMA
- 出版者
- Japan Association of Mineralogical Sciences
- 雑誌
- Journal of Mineralogical and Petrological Sciences (ISSN:13456296)
- 巻号頁・発行日
- vol.107, no.6, pp.226-243, 2012 (Released:2012-12-29)
- 参考文献数
- 32
- 被引用文献数
- 7 10
The structure of quatrandorite is reported for the first time from an untwinned sample from Oura mine, San Jose, Bolivia. The mineral crystallizes in P21/c, a = 19.1686 (19) Å, b = 17.160 (3) Å, c = 13.042 (2) Å, β = 90.008 (12)°, V = 4289.9 (11) Å3, Z = 4. Refinement to Robs = 5.66% was obtained with Jana2006. Quatrandorite belongs to the andorite series, whose members share two cell parameters while the third can be expressed as n × 4.3 Å, with n = 2, 4 and 6 for ramdohrite (uchucchacuaite, fizelyite), quatrandorite and senandorite, respectively. Both quatrandorite and senandorite are strongly pseudosymmetric up to Cmcm with one parameter corresponding to n = 1 (∼ 4.3 Å). The hypothetical structure corresponding to Cmcm is also the aristotype common to both minerals. The strong structural similarity of quatrandorite and senandorite may explain their co-existence in some samples, which has in the past led to hypothesize the existence of a further member of the series, nakaséite, which was however later shown to consist of a random stacking of the two minerals. The Cmcm aristotype is not common to the n = 2 minerals (uchucchacuaite, ramdohrite, fizelyite), which are thus structurally less closely related to the two other members. A common aristotype to all three minerals can nevertheless be obtained via a different path, which leads to Cmme with the same cell parameters as Cmcm; the degree of pseudo-symmetry in this supergroup is however lower and there remain a difference in one sulfur position in this aristotype. It nevertheless confirms previous reports in the literature stating that the bulk of the structure of the minerals of this series can be reduced to a common principle, essentially a distorted galena; the departures from it are however crucial for the realization of the individual structures.