GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Mineralogical Society of America  (3)
  • Chemistry/Pharmacy  (3)
Material
Publisher
  • Mineralogical Society of America  (3)
Person/Organisation
Language
Years
Subjects(RVK)
  • Chemistry/Pharmacy  (3)
RVK
  • 1
    Online Resource
    Online Resource
    Ruizhongite, (Ag2☐)Pb3Ge2S8, a thiogermanate mineral from the Wusihe Pb-Zn deposit, Sichuan Province, Southwest China
    Mineralogical Society of America ; 2023
    In:  American Mineralogist Vol. 108, No. 9 ( 2023-09-1), p. 1818-1823
    Details
    In: American Mineralogist, Mineralogical Society of America, Vol. 108, No. 9 ( 2023-09-1), p. 1818-1823
    Abstract: Ruizhongite (IMA2022-066), (Ag2☐)Pb3Ge2S8, is a thiogermanate of economic importance discovered in the Wusihe Pb-Zn deposit in Sichuan Province, southwestern China. This mineral occurs as anhedral grains 1–10 μm in size. It is gray and opaque, with a metallic luster and black streak, closely associated with galena and pyrite in a sphalerite matrix. Under reflected light, it displays a greenish-gray color without internal reflection. Its reflectance values in air (R %) based on SiC as the reference material are 30.5, 32.2, 34, and 34.1 for corresponding wavelengths of 650, 589, 470, and 546 nm, respectively. According to the average of 18 electron microprobe analyses, Pb (57.37 wt%), S (21.39 wt%), Ge (11.53 wt%), Ag (7.34 wt%), Zn (1.57 wt%), and Fe (0.27 wt%) constitute 99.46 wt% of ruizhongite. The empirical formula based on the 8 S apfu is (Ag0.82Pb0.32Zn0.28Fe0.06)Σ1.48Pb3Ge1.9S8, and (Ag2☐)Pb3Ge2S8 is its ideal formula. Ruizhongite displays a cubic structure, space group I43d (#220), with the unit-cell parameters a = 14.0559(2), V = 2777.00(7), Z = 8, and the calculated density is 5.706 g/cm3. The strongest powder X-ray diffraction lines [d in Å (I) (hkl)] are 3.755 (100) (123), 3.511 (76) (004), 2.992 (73) (233), 2.574 (21) (125), 2.482 (79) (044), 2.276 (46) (235), 1.784 (39) (237), and 2.075 (24) (136). The structure of ruizhongite was determined using single-crystal XRD and was refined to an R1 of 0.0323 for all 2594 (474 unique) reflections. The structure comprises a non-centrosymmetric arrangement of [GeS4] 4− tetrahedra, forming two interstice sites: fully occupied Pb1 and partially occupied Ag1, aligned in the directions of a-, b-, and c-axes. Ruizhongite was named in honor of Ruizhong Hu (1958), an eminent Chinese ore geochemist. The discovery of ruizhongite has significant implications for the occurrence and enrichment mechanism of Ge in sphalerite and other metallic minerals.
    Type of Medium: Online Resource
    ISSN: 0003-004X , 1945-3027
    URL: Article
    DOI: 10.2138/am-2023-9000
    RVK:
    VA 1700
    Language: English
    Publisher: Mineralogical Society of America
    Publication Date: 2023
    detail.hit.zdb_id: 3514-2
    detail.hit.zdb_id: 2045960-9
    SSG: 13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Synthesis of boehmite-type GaOOH: A new polymorph of Ga oxyhydroxide and geochemical implications
    Mineralogical Society of America ; 2023
    In:  American Mineralogist Vol. 108, No. 9 ( 2023-09-1), p. 1773-1780
    Details
    In: American Mineralogist, Mineralogical Society of America, Vol. 108, No. 9 ( 2023-09-1), p. 1773-1780
    Abstract: Gallium (Ga) and aluminum (Al) belong to group IIIA elements in the periodic table. They show a coupled geochemical behavior in most natural systems and are considered as “geochemical partners.” However, compared with the principal oxyhydroxides of Al in nature, gibbsite [Al(OH)3], boehmite (γ-AlOOH), and diaspore (α-AlOOH), only the analogs söhngeite [Ga(OH)3] and tsumgallite (α-GaOOH) were reported. In this work, boehmite-type GaOOH (γ-GaOOH), a new polymorph of GaOOH, was synthesized for the first time using boehmite (γ-AlOOH) as a template. The synthesized γ-GaOOH was characterized by a series of techniques, including X-ray diffraction (XRD), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and selected area electron diffraction (SAED). Furthermore, a model based on the boehmite structure was successfully applied to define the γ-GaOOH structure by the Rietveld method. Results from sample characterization and structural refinement support the successful synthesis of boehmite-type GaOOH, and thus it is referred to as γ-GaOOH. The synthesis of γ-GaOOH in the laboratory is valuable to understanding the Ga geochemistry and its enrichment process in Ga-rich boehmite in coal and bauxite.
    Type of Medium: Online Resource
    ISSN: 0003-004X , 1945-3027
    URL: Article
    DOI: 10.2138/am-2022-8568
    RVK:
    VA 1700
    Language: English
    Publisher: Mineralogical Society of America
    Publication Date: 2023
    detail.hit.zdb_id: 3514-2
    detail.hit.zdb_id: 2045960-9
    SSG: 13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    The composition of garnet in granite and pegmatite from the Gangdese orogen in southeastern Tibet: Constraints on pegmatite petrogenesis
    Mineralogical Society of America ; 2021
    In:  American Mineralogist Vol. 106, No. 2 ( 2021-02-1), p. 265-281
    Details
    In: American Mineralogist, Mineralogical Society of America, Vol. 106, No. 2 ( 2021-02-1), p. 265-281
    Abstract: Two generations of garnet are recognized in a granite and a pegmatite from the Gangdese orogen in southeastern Tibet on the basis of a combined study of petrography, major and trace element profiles, and garnet O isotopes. Zircon U-Pb dating and Hf-O isotope compositions also help constrain the origin of both granite and pegmatite. The first generation of garnet (Grt-I) occurs as residues in the center of garnet grains, and it represents an early stage of nucleation related to magmatic-hydrothermal fluids. Grt-I is dark in backscattered electron (BSE) images, rich in spessartine, and poor in almandine and grossular. Its chondrite-normalized rare earth element (REE) patterns show obvious negative Eu anomalies and depletion in heavy REE (HREE) relative to middle REE (MREE). The second generation of pegmatite garnet (Grt-II) occurs as rims of euhedral garnets or as patches in Grt-I domains of the pegmatite, and it crystallized after dissolution of the preexisting pegmatite garnet (Grt-I domains) in the presence of the granitic magma. Compared with Grt-I, Grt-II is bright in BSE images, poor in spessartine, and rich in almandine and grossular contents. Its chondrite-normalized REE patterns exhibit obvious negative Eu anomalies but enrichment in HREE relative to MREE. The elevation of grossular and HREE contents for Grt-II relative to Grt-I domains indicate that the granitic magma had higher contents of Ca than the magmatic-hydrothermal fluids. The garnets in the granite, from core to rim, display homogenous profiles in their spessartine, almandine, and pyrope contents but increasing grossular and decreasing REE contents. They are typical of magmatic garnets that crystallized from the granitic magma. Ti-in-zircon temperatures demonstrate that the granite and pegmatite may share the similar temperatures for their crystallization. Grt-II domains in the pegmatite garnet have the same major and trace element compositions as the granite garnet, suggesting that the pegmatite Grt-II domains crystallized from the same granitic magma. Therefore, the pegmatite crystallized at first from early magmatic-hydrothermal fluids, producing small amounts of Grt-I, and the fluids then mixed with the surrounding granitic magma. The U-Pb dating and Hf-O isotope analyses of zircons from the granite and pegmatite yield almost the same U-Pb ages of 77–79 Ma, positive eHf(t) values of 5.6 to 11.9, and d18O values of 5.2 to 7.1‰. These data indicate that the granite and pegmatite were both derived from reworking of the juvenile crust in the newly accreted continental margin prior to the continental collision in the Cenozoic.
    Type of Medium: Online Resource
    ISSN: 0003-004X , 1945-3027
    URL: Article
    DOI: 10.2138/am-2020-7388
    RVK:
    VA 1700
    Language: English
    Publisher: Mineralogical Society of America
    Publication Date: 2021
    detail.hit.zdb_id: 3514-2
    detail.hit.zdb_id: 2045960-9
    SSG: 13
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...