Roselite
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Roselite is a rare arsenate mineral with chemical formula: Ca₂[AsO₄]₂·H₂O. It was first described in 1825 for an occurrence in the Rappold mines of Schneeberg, Saxony, Germany and named by Armand Lévy after German mineralogist Gustav Rose. Wikipedia
Cleavage: Perfect
Color: Dark rose red, pink
Crystal class: Prismatic (2/m); (same H-M symbol)
Crystal habit: Elongated crystals and spherical aggregates and druses
Crystal system: Monoclinic
Formula (repeating unit): Ca2(Co2+, Mg)2·H2O+
Optical properties: Biaxial (−)