Boleite
Boleite is a very rare gem because crystals are very small and usually opaque. Transparent, fact table crystals are rarely found. Boleite’s intense blue color is very attractive. Boleite is a silver bearing Halide mineral that also contains lead and copper. Boleite is closely related to Diaboleite (“distinct from” Boleite), Pseudoboleite (“false” Boleite) and Cumengeite. All four minerals are secondary copper minerals. They are also Halide minerals. The Halides are a group of minerals whose principal anions are halogens. Halogens are a special group of elements that usually have a charge of negative one when chemically combined. The halogens that are commonly found in nature include Fluorine, Chlorine, Iodine, and Bromine. Halides tend to have fairly simply ordered structures and therefore a high degree of symmetry.
Sources are the type locality, Boleo, Baja California, Mexico; Chile; and Broken Hill, N.S.W., Australia.
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Category: |
Halide mineral |
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Chemical Formula: |
KPb26Ag9Cu24Cl62(OH)48 |
| Potassium Lead Silver Chloride Hydroxide | |
| Molecular Weight: | 10,936.64 gm |
| Composition: | Potassium | 0.36 % | K | 0.43 % | K2O |
| Copper | 13.94 % | Cu | 15.70 % | Cu2O | |
| Silver | 8.88 % | Ag | 9.54 % | Ag2O | |
| Hydrogen | 0.44 % | H | 3.95 % | H2O | |
| Lead | 49.26 % | Pb | 53.06 % | PbO | |
| Chlorine | 20.10 % | Cl | 20.10 % | Cl | |
| – | – % | Cl | -4.54 % | -O=Cl2 | |
| Oxygen | 7.02 % | O | |||
| 100.00 % | 100.00 % | = TOTAL OXIDE |
| Crystallography: | Isometric – Hexoctahedral |
| Crystal Habit: | Crystals Crystals cubic, to 2 cm, commonly surficial layered with or overgrown by pseudoboleite |
| Twinning: | Pseudocubically interpenetrate common |
| Cleavage: | Perfect on {001}, Good on {101} |
| Fracture: | Irregular/Uneven |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.0 – 3.5 |
| Density: | 5.054 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Barely Detectable; GRapi = 4.47 (Gamma Ray American Petroleum Institute Units) |
| Other: | Inert in water. Soluble in HNO3. |
| Color: | Deep Blue, Indigo Blue |
| Transparency: | Transparent to Translucent |
| Luster: | Weakly Vitreous, Pearly |
| Refractive Index: | Isotropic, n=2.05, Uniaxial ( – ) |
| Birefringence: | 0.00 (Isotropic) |
| Dispersion: | n/a |
| Pleochroism: |
None |
