English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Manganoquadratite, ideally AgMnAsS3, is a new mineral from the Uchucchacua polymetallic deposit, Oyon district, Catajambo, Lima Department, Peru. It occurs as dark gray, anhedral to subhedral grains up 0.5 mm across, closely associated with alabandite, Mn-rich calcite, Mn-rich sphalerite, proustite, pyrite, pyrrhotite, tennantite, argentotennantite, stannite, and other unnamed minerals of the system Pb-Ag-Sb-Mn-As-S. Manganoquadratite is opaque with a metallic luster and possesses a reddish-brown streak. It is brittle, the Vickers microhardness (VHN 10 ) is 81 kg/mm 2  (range 75-96) (corresponding Mohs hardness of 2-2½). The calculated density is 4.680 g/cm 3  (on the basis of the empirical formula). In plane-polarized reflected light, manganoquadratite is moderately bireflectant and very weakly pleochroic from dark gray to a blue gray. Internal reflections are absent. Between crossed polars, the mineral is anisotropic, without characteristic rotation tints. Reflectance percentages (R min  and R max ) for the four standard COM wavelengths are 29.5, 31.8 (471.1 nm), 28.1, 30.5 (548.3 nm), 27.3, 29.3 (586.6 nm), and 26.0, 28.2 (652.3 nm), respectively. Manganoquadratite is tetragonal, space group P4 3 22, with unit-cell parameters: a = 5.4496(5), c = 32.949(1) Å, V = 978.5(1) Å 3 , c:a = 6.046, Z = 8. The structure, refined to R 1  = 0.0863 for 907 reflections with F o  &gt; 4σ(F o ), consists of a stacking along [001] of alabandite-like Mn 2 S 2  layers connected to each to other by a couple of AgAsS 2  sheets where As 3+  forms typical AsS 3  groups, whereas Ag +  cations are fivefold coordinated. The six strongest lines in the observed X-ray powder-diffraction pattern [d in Å (I/I 0 ) (hkl)] are: 3.14 (60) (116), 2.739 (50) (0 0 12), 2.710 (100) (200), 1.927(70) (2 0 12 + 220), 1.645 (25) (3 0 16), and 1.573 (20) (2 2 12). Electron microprobe analyses gave the chemical formula (on the basis of six atoms) (Ag 0.95 Cu 0.05 ) Σ=1.00  (Mn 0.96 Pb 0.04 ) Σ=1.00 (As 0.87 Sb 0.14 ) Σ=1.01 S 2.99 , leading to the simplified formula AgMnAsS 3 . The name was chosen to indicate the close analogy of the formula and unit-cell dimensions with quadratite, Ag(Cd,Pb)(As,Sb)S 3 . The new mineral and mineral name have been approved by the Commission on New Minerals, Nomenclature and Classification, IMA 2011-008.

american mineralogist

Manganoquadratite, AgMnAsS 3 , a new manganese-bearing sulfosalt from the Uchucchacua polymetallic deposit, Lima Department, Peru: Description and crystal structure