Important minerals of manganese are pyrolusite manganite and hausmannite
(Roberts et al.
Ilfeld is also the type locality for another manganese oxide: hausmannite
2) at Jordan Mountain contains manganite intergrown with pyrolusite, and reduced amounts of hausmannite
and psilomelane (Rose and Johnson 1990; Merlini 1998).
The hematite specimens, in thumbnail to small-cabinet sizes, show tabular, mirror-faced and brilliantly lustrous, jet-black hematite crystals from 2 to 5 cm; some of the specimens are loose single crystals and crystal groups, while others show the hematite crystals, some partly overgrown by white oyelite, resting on matrix of black massive hausmannite
Oxides such as goethite (Fe), hausmannite
(Mn), and alumina (Al) have large ratios of surface area to mass, and avidly sorb Cd when the pH exceeds their respective sorption edges, i.
A few larger specimens--to 10 X 15 cm--have olmiite crystals scattered on a matrix of dull black hausmannite
, with little spheres of chalky white calcite.
The Wyndham pit yielded manganese oxide minerals, including well-crystallized specimens of twinned black hausmannite
crystals and also some attractive specimens of pink rhodochrosite (collected by Sir Arthur Russell in the 1930s).
The type material came from a pocket in massive braunite and hausmannite
and was associated with henritermierite, calcite, bultfonteinite and hematite.
They're all here, in multiple samples ranging in quality from "study grade" to absolutely superb: Freiberg acanthite and stephanite, Schneeberg proustite and erythrite and roselite and uranium-bearing species, Andreasberg pyrargyrite and dyscrasite and fluorite and pink apophyllite, Siegerland malachite and anglesite and millerite and galena, Schwarzwald fluorite and barite and silver, Obermoschel cinnabar and moschellandsbergite, Ems pyromorphite and cerussite, Johanngeorgenstadt mimetite, Ohrenstock hausmannite
, Fichtelgebirge topaz and microcline and herderite, Ehrenfriedersdorf cassiterite and fluorapatite, Ilfeld manganite, Ronneburg whewellite, Hagendorf phosphates .
Well, in late 2003 and early 2004, some old mine dumps near Ilfeld yielded about 250 fairly handsome, small specimens of hausmannite
pseudomorphs after manganite, as jet-black prismatic crystals to 3 cm shot through, or protruding from, massive manganese oxide matrix.
Another mineral discovery available in quantity in 1994 was hausmannite
from the N'Chwaning mine, South Africa.
See Andina, Bolsa Mururata 1) Negra, Aceromarca, Chojlla Mutun Cryptomelane, hausmannite
, hematite, magnetite (30 billion tons of iron ore), pyrolusite Napa Potassium-alum, sulfur, ulexite Negra Arseniosiderite, pyrolusite Negro Pabellon Cassiterite, hisingerite, (Also called Japo) pyrrhotite, siderite, vivianite Nueva Venecia Columbite, ilmenite (to 3.