Akrochordite is a rare hydrated manganese-magnesium arsenate hydroxide and is isostructural with guanacoite. It forms monoclinic, prismatic, yellowish red-brown to pale brown, translucent, sub-vitreous to resinous crystals; also may be in radial aggregates and subparallel sheaves. It typically as wart-like or spherical aggregates of minute crystals. Akrochordite was discovered in 1915 and named by Gustav Flink in 1922 from the Greek word, akrochordon, "a wart," in reference to its appearance. Akrochordite occurs in hausmannite ore from a metamorphosed iron–manganese orebody and in fractures in a metamorphosed zinc deposit. The type locality is Langban, Filipstad, Värmland, Sweden. Other notable localities include: Sterling Hill, New Jersey, USA, Hilfe Gottes mine, Wiemannsbucht, Bad Grund, Osterode district, Lower Saxony, Germany; and the Milgun Variscite mine, Milgun Station, Meekatharra Shire, Western Australia, Australia.
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