Most of the spots showed the presence of Hausmannite
and Braunite (Figs.
Lokhande, "A novel chemical synthesis of interlocked cubes of hausmannite
[Mn.sub.3][O.sub.4] thin films for supercapacitor application," Journal of Alloys and Compounds, vol.
During the 19th-century heyday of mining the so-called "Ilfeld-Mangan" mine area in Silberbachtal (one of the few workings to have received its own name) measured 2.1 million square meters, and produced chiefly pyrolusite and hausmannite
ore from irregular stringers and pods (Rumscheidt, 1926).
Based on simulations during the correction of the pH possible solid phases formed include Fe(OH)3, [Fe.sub.3](OH)8, goethite (FeOOH), hematite and maghemite ([Fe.sub.2][O.sub.3]), magnetite ([Fe.sub.3][O.sub.4]), gibbsite (Al(OH)3), basaluminite [([Al.sub.4](OH).sub.10]S[O.sub.4]),boehmite and diaspore (AlOOH), jurbanite (AlOHS[O.sub.4]), U[O.sub.2][(OH).sub.2] and schoepite (U[O.sub.2][(OH).sub.2]*[H.sub.2]O), hausmannite
, manganite, and pyrolusite.
In contrast, if hausmannite
is an appropriate model for the (hydrous)oxides of Mn in soils, one might have expected the effects to have been observed, given that the sorption edge is pH 3-4 (Backes et al.
It occurred very sparingly at the surface of cavities and fractures in a manganese ore containing tephroite, bementite, braunite, hausmannite
Associated minerals are: rhodochrosite, friedelite, hubnerite, sphalerite, stilpnomelane, albite, barite, hausmannite
, tephroite, welinite and an unidentified manganese vanadate.
The matrix of the philolithite-bearing fissures is a calcite-rich Mn oxide ore, dominated by braunite with lesser amounts of hausmannite
. Other Mn-bearing silicates, mainly pyrochroite and a reddish brown manganoan phlogopite, are ubiquitous in smaller amounts.
It is from the N'Chwaning mine, South Africa, and must be absolutely the world's finest specimen of hausmannite
. We're used to seeing this material as large, bristly, dull or medium-lustered compound black octahedral crystals on massive garnet matrix, and these are remarkable enough for the species.
The mineral occurs as massive granular aggregates and simple tetragonal tablets in small cracks in Mn-rich skarn consisting principally of fine-grained hausmannite
, biotite (manganophyllite), and calcite.
The terminated prisms of gaudefroyite can attain 1.5-cm, rising in jumbles from black massive hausmannite
matrix, with occasional 5-mm white crystals which may be calcite, thaumasite, ettringite, or all of these.
Occurrence: In a matrix consisting primarily of braunite, sugilite and hausmannite
, cut by pectolite veinlets (0.1-1 mm wide) in which the mineral occurs.