Arthurite
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Arthurite is a mineral composed of divalent copper and iron ions in combination with trivalent arsenate, phosphate and sulfate ions with hydrogen and oxygen. Wikipedia
Color: Apple-green to bluish-green
Crystal class: Prismatic (2/m); (same H-M symbol)
Crystal habit: Acicular, prismatic, spherical
Crystal system: Monoclinic
Formula (repeating unit): CuFe23+2·4H2O
Space group: P21/c