A Ferric Iron Equivalent of Hematolite from Sterling Hill, New Jersey and Långban, Sweden

Pete J. Dunn and Donald R. Peacor
Department of Mineral Sciences, Smithsonian Institution, Washington, DC 20560
Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109

Abstract: An unnamed Fe3+ analogue of hematolite is described from Sterling Hill, New Jersey and Långban, Sweden. Eight microprobe analyses are in good agreement with ratios derived from a prior analysis which yielded: Al2O3 0.24, Fe2O3 10.85, MgO 10.61, MnO 41.76, As2O3 6.65, As2O5 15.29, H2O 13.23 (rem. = 1.63), sum = 100.26 %. Single-crystal study indicated that this compound is hexagonal with a = 8.28 Å, but the value of c could not be well-defined due to complex polytypism giving rise to diffuse and poorly resolved reflections along c*. In one case, a value of c = 72.69 Å was dominant. All values that could be determined were multiples of approximately 12 Å. The strongest lines in the X-ray powder diffraction pattern are: 2.400(100), 1.563(100), 6.09(80), 3.42(50), and 5.13(50). This compound is dark red and occurs as platy hexagonal crystals in clusters associated with a wide variety of species in varied assemblages. It remains unnamed because of the ambiguity arising from polytypism.

Mineralogical Magazine; September 1983 v. 47; no. 344; p. 381-385; DOI: 10.1180/minmag.1983.047.344.15
© 1983, The Mineralogical Society
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