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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Carlfrancisite, Mn 3  2+ (Mn 2+ ,Mg,Fe 3+ ,Al) 42 (As 3+ O 3 ) 2 (As 5+ O 4 ) 4 [(Si,As 5+ )O 4 ] 6 [(As 5+ ,Si)O 4 ] 2 (OH) 42 , is a new mineral from the Kombat mine, Otavi Valley, Namibia, and occurs as curved platy aggregates ~2 cm across on a matrix of Mn arsenates and oxides. It is yellowy orange to pale yellow with a very pale-yellow streak, translucent with a vitreous to opalescent luster, and does not fluoresce under ultraviolet light. Cleavage is micaceous on {001}, and no parting or twinning was observed. Mohs hardness is 3, and carlfrancisite is brittle with a hackly fracture. The calculated density is 3.620 g/ cm 3 . Optical properties were measured with a Bloss spindle stage for the wavelength 590 nm using a gel filter. The indices of refraction are e = 1.756, w = 1.758, and it is non-pleochroic. Carlfrancisite is trigonal, space group R3̄c, a = 8.2238(2), c = 205.113(6) Å, V = 12 013.5(4) Å 3 , Z = 6, c:a = 1:24.941. The seven strongest lines in the X-ray powder-diffraction pattern are as follows: d (Å), I, (hkl): 2.826, 100, (2̄ 2 44); 2.371, 88, (2̄ 3 40, 1̄ 3 41); 1.552, 84, (1̄ 5 0); 2.676, 63, (2̄ 3 7); 3.243, 54, (0 1 56, 1̄ 2 39); 4.107, 48, (1̄ 2 0); 2.918, 47, (0 2 40). Chemical analysis by electron microprobe and crystalstructure refinement gave As 2 O 5  13.07, As 2 O 3  3.18, P 2 O 5  0.50, V 2 O 5  0.74, SiO 2  8.96, Al 2 O 3  0.78, FeO 0.22, MnO 53.25, MgO 9.37, H 2 O(calc) 8.42, sum 98.49 wt%. The H 2 O content and the valence states of As were determined by crystal-structure analysis. The empirical formula is Mn 2+   33.55 Mg 10.39 Fe 2+  0.14 Al 0.68  As 3+  1.44 (Si 6.67 P 0.32 V 5+   0.37 As 5+  5.08 )O 54  (OH) 42  on the basis of 96 anions with (OH) = 42 apfu. The structure of carlfrancisite is closely related to that of mcgovernite and turtmannite.

american mineralogist

Carlfrancisite: Mn 3   2+ (Mn 2  + ,Mg,Fe 3+ ,Al) 42 (As 3+ O 3 ) 2 (As 5+ O 4 ) 4 [(Si,As 5+ )O 4 ] 6 [(As 5+ ,Si)O 4 ] 2 (OH) 42 , a new arseno-silicate mineral from the Kombat mine, Otavi Valley, Namibia