Laurionite (PbCl(OH)) is a lead halide mineral. It forms colorless to white crystals in the orthorhombic crystal system and is dimorphous with paralaurionite, both members of the matlockite group. It was first described in 1887 for an occurrence in the Laurium District, Attica, Greece and named after the town Laurium. It occurs as an oxidation pro... Found on http://en.wikipedia.org/wiki/Laurionite