... are described, which together with manganarsite are analogous to the three principal members of the friedelite group, manganpyrosmalite, schallerite, and friedelite. Manganarsite and its polymorphs are 7-Å layered structures that apparently differ in the stacking sequence of pyrochroite layers, as is true...

.... The schallerite formula can be derived from that of friedelite by the substitution of two O for two (OH), coupled with the addition of As 3+ (OH). Schallerite is apparently not a true polytype of manganpyrosmalite. A second paragenesis of spherulitic schallerite in rhodonite is described in detail. Caryopilite...

...D. R. Peacor; E. J. Essene Abstract Electron microprobe analyses of caryopilite show that the octahedral cation to silicon ratio is close to 8:6, consistent with a friedelite structure type, rather than the 9:6 ratio expected for a serpentine type. The powder X-ray diffraction patterns are very...

...Max H. Hey Abstract Frondel and Bauer (1953) have shown that the friedelite family of minerals can be divided into three sections: pyrosmalite and mangan-pyrosmalite, with c = 7.15 Å; schallerite, with c≈ 14.3 Å (both Type I with As 2 O 3 ≈ 12% and Type II with As 2 O 3 ≈ 6 to 8%); and friedelite...

....). Uniaxial negative, with ω 1.669, ε 1.631 (Na). Hardness 4½. Perfect cleavage (0001). Color pure brown. Manganpyrosmalite, schallerite and friedelite are polymorphs representing multiple stacking variants along [0001] of layer-structures, analogous to the micas. Cell dimensions (new data): a 0 c 0 Lattice...

...L. H. Bauer; Harry Berman Abstract The problem of the isomorphism of friedelite and a number of other minerals similar in crystallographic and optical properties, and related chemically, has attracted several investigators. New chemical and physical data recently determined on some minerals...

...Figure 9. Thin-section photographs (transmitted and reflected light) and false-colour mineral maps of typical samples from Cluster 1. ( A ) Jacobsite-rich ovoids in a finely laminated matrix of friedelite and kutnohorite/Mn-dolomite (GHEX096/140.3m). An ovoid with jacobsite, gonyerite...

.... Polarized-light microscopy shows the rods to be oriented uniformly parallel to the c axis of willemite, and to have hexagonal or pseudohexagonal cross-sections. Phases identified by standardless EDS analysis and electron back-scatter diffraction include franklinite, friedelite, zincian kutnohorite...

...Joel Brugger; Michel Bonin; Kurt J. Schenk; Nicolas Meisser; Peter Berlepsch; Alain Ragu Abstract Nabiasite, ideally BaMn 9 [(V,As)O 4 ] 6 (OH) 2 , is a new mineral which occurs in rhodochrosite-, friedelite- and barite-bearing veinlets crosscutting Mn ores at the historic Pla de Labasse deposit...

... made by A.C. Freeze and R.M. Thompson of the mineral they tentatively identified as friedelite. These mineralogists believed that the mineral somehow differed from friedelite, but they lacked the crystallographic evidence to establish it as a new mineral.--Modified journal abstract. © 1984...

... silicates (e.g., friedelite and chlorite), and trace quantities of alabandite (MnS) and pyrolusite (MnO 2 ). The replacement of pyrolusite by rhodochrosite suggests that the initial manganese precipitates were Mn(IV)-oxides. Precipitation within an oxic water column is supported by shale-normalized REE+Y...

... and parageneses in both localities are distinct: minute isometric grains up to 15 μm in size, associated with friedelite, jacobsite, pennantite, manganhumite series minerals (alleghanyite, sonolite), sarkinite, tilasite, and retzian-(La) are typically embedded into calcite-rhodochrosite veinlets (Ushkatyn-III...

... district, central Pyrénées, France, in and around quartz-rhodochrosite-sulphide veinlets cross-cutting the rhodochrosite ore in greenschist-facies Lower Carboniferous radiolarite. Other associated minerals are vuorelainenite, chalcopyrite, vanadian spessartine, and friedelite. The structural formula...

... stage (I) as the anhydrous silicates ferroan tephroite, johannsenite, rhodonite, and bustamite. During the early main stage (II) ferroan tephroite was replaced by friedelite and magnetite under oxidizing conditions at a relatively low pH. Pb, Zn, Fe, Cu, and B were introduced; principal sulfides...