| Laurionite | |
| Category: | Halide minerals |
| Formula: | PbCl(OH) |
| Imasymbol: | Lri[1] |
| Strunz: | 3.DC.05 |
| System: | Orthorhombic |
| Class: | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Symmetry: | Pnma |
| Unit Cell: | a = 7.111, b = 9.6987 c = 4.0203 [Å]; Z = 4 |
| Color: | Colorless, white |
| Habit: | Elongated tabular prismatic crystals |
| Cleavage: | Distinct on |
| Tenacity: | Flexible |
| Mohs: | 3–3.5 |
| Luster: | Adamantine, pearly |
| Streak: | White |
| Diaphaneity: | Transparent |
| Gravity: | 6.241 |
| Opticalprop: | Biaxial (−) |
| Refractive: | nα = 2.077 nβ = 2.116 nγ = 2.158 |
| Birefringence: | δ = 0.081 |
| 2V: | Measured: 70° |
| Solubility: | Sleight in cold water |
| References: | [2] [3] [4] [5] |
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.[2]
It was first described in 1887 for an occurrence in the Laurium District, Attica, Greece, and named after the town Laurium.[2] It occurs as an oxidation product in lead ore deposits, and is also produced on lead-bearing slag by reaction with saline solutions. It occurs associated with paralaurionite, penfieldite, fiedlerite, phosgenite, cerussite and anglesite.[3]