| Allanpringite | |
| Category: | Phosphate mineral |
| Formula: | Fe3+3(PO4)2(OH)3·5H2O |
| Imasymbol: | Apg[1] |
| Molweight: | 498.07 g/mol |
| Strunz: | 8.DC.50 |
| Dana: | 42.10.02.02 |
| System: | Monoclinic |
| Class: | Prismatic (2/m) (same H-M symbol) |
| Symmetry: | P21/n |
| Unit Cell: | a = 9.777, b = 7.358 c = 17.83 [Å]; β = 92.19°; Z = 4 |
| Color: | Pale brownish yellow |
| Habit: | Acicular |
| Cleavage: | perfect, good |
| Fracture: | Irregular/uneven |
| Tenacity: | Brittle |
| Mohs: | 3 |
| Luster: | Vitreous |
| Refractive: | nα = 1.662 nβ = 1.675 nγ = 1.747 |
| Opticalprop: | Biaxial (+) |
| Birefringence: | 0.085 |
| 2V: | 48° (calc.) |
| Streak: | Pale yellowish white |
| Gravity: | 2.54 (meas.), 2.583 (calc.) |
| Diaphaneity: | Translucent to transparent |
| References: | [2] [3] |
Allanpringite is a phosphate mineral named after Australian mineralogist Allan Pring of the South Australian Museum. Allanpringite is a Fe3+ analogue Al-phosphate mineral wavellite, but it has a different crystal symmetry – monoclinic instead of orthorhombic in wavellite. It forms needle-like crystals, which are always twinned and form parallel bundles up to about 2 mm long. They are often found in association with other iron phosphates in abandoned iron mines.[2] [4]