High Quality Content by WIKIPEDIA articles! Boleite is a complex halide mineral with formula: KPb26Ag9Cu24(OH)48Cl62. It was first described in 1891 as an oxychloride mineral. It is an isometric mineral which forms in deep blue cubes. There are numerous minerals related to boleite, such as pseudoboleite and cumengite, and these all have the same complex crystal structure (Martens 2003). They all contain bright blue cubic forms and are formed in altered zones of lead and copper deposits, produced during the reaction of chloride bearing solutions with primary sulfide minerals (Rouse, 1973).