| Boleite | |
| Category: | Halide mineral |
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| Formula: | KPb26Ag9Cu24(OH)48Cl62 |
| Imasymbol: | Bol[1] |
| Strunz: | 3.DB.15 |
| System: | Isometric |
| Class: | Hexoctahedral (mm) H-M symbol: (4/m 2/m) |
| Symmetry: | Pmm |
| Unit Cell: | a = 15.29 Å; Z = 1 |
| Color: | Deep Prussian blue to indigo |
| Habit: | Cubic crystals |
| Cleavage: | [001] perfect |
| Fracture: | Uneven |
| Mohs: | 3.0 – 3.5 |
| Luster: | Vitreous to pearly |
| Refractive: | n = 2.05 |
| Opticalprop: | Isotropic |
| Streak: | Greenish blue |
| Gravity: | 5.054 |
| Diaphaneity: | Translucent |
| Other: | Radioactive 0.36% (K) |
| References: | [2] [3] [4] |
Boleite is a complex halide mineral with formula: KPb26Ag9Cu24(OH)48Cl62.[3] 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, cumengite, and diaboleite, and these all have the same complex crystal structure.[5] 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.[6]
The external property of a boleite crystal structure indicates its cubic structure. It is classified under the isometric crystal class. Boleite has a perfect cleavage in the [001] direction, and has a very dark glossy blue color with a light greenish-blue color streak. Twinning is best shown in this mineral by notches along the interpenetrated angles, which results in a crystal habit of pseudocubic penetration twinning along three different angles perpendicular to one another. Boleite has cubes over half an inch on each side, which consist of pseudo-octahedral tetragonal dipyramids.[7]
Boleite was first collected as a very minor ore of silver, copper and lead at Boleo, Mexico.[6] Boleite was named after its place of discovery, El Boleo mine, on the Baja Peninsula, near Santa Rosalia, Mexico.[3]
Minerals associated with boleite include pseudoboleite, cumengeite, atacamite, anglesite, cerussite, phosgenite and gypsum at the type locality in Boleo, Mexico. In the Mammoth-St. Anthony mine of Arizona associated minerals include pseudoboleite, anglesite, cerussite, atacamite, paratacamite, leadhillite, paralaurionite, caledonite, phosgenite, matlockite and bideauxite.[2]