Pseudomalachite
Pseudomalachite is a phosphate of copper with hydroxyl, named from the Greek for "false" and "malachite", because of its similarity in appearance to the carbonate mineral malachite, Cu₂(OH)₂. Both are green coloured secondary minerals found in... Wikipedia
Crystal system: Monoclinic
Crystal class: Prismatic (2/m); (same H-M symbol)
Formula mass: 575.7 g/mol
Formula (repeating unit): Cu5(PO4)2(OH)4
Luster: Vitreous
Optical properties: Biaxial (−)
Solubility: Soluble in acids but without effervescence (in contrast to malachite which effervesces with warm HCl)