Childrenite
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| Childrenite | |
|---|---|
 | |
| General | |
| Category | Phosphate minerals |
| Formula | (Fe2+ ,Mn)2+ AlPO 4(OH) 2•H 2O |
| IMA symbol | Chd[1] |
| Strunz classification | 8.DD.20 |
| Crystal system | Orthorhombic |
| Crystal class | Pyramidal (mm2) (same H-M symbol) |
| Space group | Bba2 |
| Unit cell | a = 10.41 Å, b = 13.42 Å, c = 6.92 Å; Z = 8 |
| Identification | |
| Color | Yellowish brown, brown, clove-brown; colorless in transmitted light. |
| Cleavage | Poor/indistinct on {100} |
| Fracture | Irregular/uneven, sub-conchoidal |
| Mohs scale hardness | 5 |
| Luster | Vitreous, resinous |
| Streak | White |
| Diaphaneity | Transparent, translucent |
| Specific gravity | 3.11–3.19 |
| Optical properties | Biaxial (−) |
| Refractive index | nα = 1.644 – 1.649 nβ = 1.662 – 16.830 nγ = 1.671 – 1.691 |
| Birefringence | δ = 0.027 – 0.042 |
| Pleochroism | Visible |
| 2V angle | Measured: 40° to 45°, calculated: 50° |
| Dispersion | r > v strong |
| Solubility | Soluble in acids. |
| References | [2][3][4] |
Childrenite is a rare hydrated phosphate mineral with elements iron, manganese, aluminium, phosphorus, oxygen and hydrogen. Its chemical formula is (Fe2+
,Mn)2+
AlPO
4(OH)
2•H
2O and it has a molecular weight of 229.83 g/mol. Its specific gravity is 3.2 and it has a Mohs hardness of 4.5 to 5. It is usually translucent and non-fluorescent, with imperfect cleavage. It has a vitreous lustre with a white streak, and is brown or yellow in color. It has a conchoidal, uneven fracture, and an orthorhombic crystal system.
