hematolite

hematolite

[′he·məd·ō‚līt]
(mineralogy)
(Mn,Mg)4 Al(AsO4)(OH)8 A brownish-red mineral composed of aluminum manganese arsenate; occurs in rhombohedral crystals.
References in periodicals archive ?
Relationship to other species: The crystal structure resembles that of hematolite.
(1999) The effect of differences in coordination on ordering of polyvalent cations in close-packed structures: the crystal structure of arakiite and comparison with hematolite. Canadian Mineralogist 37, 1471-1482.
Arakiite is megascopically indistinguishable from either hematolite or dixenite and possesses the following physical properties: steak is pale brown; lustre is resinous to submetallic; diaphaneity is opaque (masses) to translucent (thin edges); non-fluorescent; hardness is estimated at 3-4; cleavage is {001} perfect; tenacity is brittle; fracture is uneven, almost subconchoidal; calculated density is 3,41 g/[cm.sup.3] (for empirical formula and unit-cell parameters derived from crystal structure).
The misidentification is certainly legitimate; arakiite is megascopically indistinguishable from dixenite and hematolite. All three minerals occur at L[dot{a}]ngban as thin foliated reddishcolored masses on ore-bearing matrix.
Araki, in close collaboration with Professor Paul Moore, solved the structures of many complex P-bearing and As-bearing phases, including those of hematolite and dixenite.
However, strong 00l reflections at 12.07, 6.046, 4.040 and the strong reflection at I.552 [dot{A}] are comparable, in both intensity and spacing, to those diffraction lines published for both hematolite and dixenite and, additionally, to the unnamed [Fe.sup.3+] analogue of hematolite (Dunn and Peacor, 1983) and to the unnamed L[dot{a}]ngban arsenate of Roberts and Dunn (1988).
Zinc is the key element which differentiates arakiite from hematolite. Both minerals have structures that are based on five close-packed repeat layers.
(1983) A ferric iron equivalent of hematolite from Sterling Hill, New Jersey and L[dot{a}]ngban, Sweden.
At Nordmark, an iron ore field consisting of several mines with some small manganese orebodies has yielded specimens as well; dump and in situ finds of several interesting minerals have been made, including rare manganese arsenates such as synadelphite, hematolite and allactite in small but attractive micromounts; also filipstadtite, manganostibite, katoptrite and alabandite.