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Mn4Mg(AsO4)2(OH)4.4H2O
Monoclinic
Akrochordite was first reported from Sterling Hill by Dunn (1981b); it has not been reported from Franklin.
Akrochordite occurs as spherical aggregates of platy crystals with a radial texture, but only one near-complete spherule (approximately 12 mm in diameter) is known. The preponderance of local material occurs as flattened, round, 5-7 mm splayed patches in vein assemblages; these aggregates have varying thicknesses and curved edges, suggesting that they were prevented from developing into hemispherulitic aggregates by tight vein sidewalls. The color is very light brown, but akrochordite is easily oxidized, and surface colors are much darker brown. The density is 3.35 g/cm3. There is no discernible fluorescence in ultraviolet. It is best identified using X-ray methods.
Akrochordite is a manganese arsenate hydroxide hydrate mineral. Local material contains very little Mg (Table 25).
Akrochordite occurs rarely in veins in calcite-rich willemite-franklinite ore, associated with sarkinite, chlorophoenicite, and a carbonate mineral. It was found in 1979 in the 1220 undercut pillar, 30 feet below the 800 level.
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| Copyright © 1995 by Pete J. Dunn |
Website
by Herb Yeates
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Link
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This
page created: January 11, 2001 |
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