Ludlamite
| Ludlamite | |
|---|---|
|
Ludlamite from the Huanuni mine, Huanuni, Bolivia | |
| General | |
| Category | Phosphate mineral |
| Formula (repeating unit) | (Fe,Mn,Mg)3(PO4)2·4H2O |
| Strunz classification | 08.CD.20 |
| Crystal symmetry |
Monoclinic prismatic H-M symbol: (2/m) Space group: P 21/a |
| Unit cell | a = 10.541(5) Å, b = 4.646(4) Å, c = 9.324(5) Å; β = 100.52°; Z = 2 |
| Identification | |
| Color | Apple-green to bright green |
| Crystal habit | Tabular crystals; massive, granular |
| Crystal system | Monoclinic |
| Cleavage | Cleavage: perfect on {001}, indistinct on {100} |
| Mohs scale hardness | 3.5 |
| Luster | Vitreous, pearly on cleavage |
| Streak | Pale greenish white |
| Diaphaneity | Translucent |
| Specific gravity | 3.12–3.19 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.650 - 1.653 nβ = 1.669 - 1.675 nγ = 1.688 - 1.697 |
| Birefringence | δ = 0.038 - 0.044 |
| 2V angle | Measured: 82° |
| References | [1][2][3] |
Ludlamite is a rare phosphate mineral with formula: (Fe,Mn,Mg)3(PO4)2·4H2O.
It was first described in 1877 for an occurrence in Wheal Jane mine in Cornwall, England and named for English mineralogist Henry Ludlam (1824–1880).
Occurrence
It occurs in granite pegmatites and as a hydrothermal alteration product of earlier phosphate bearing minerals in a reducing environment.[3] It occurs associated with whitlockite, vivianite, triploidite, triplite, triphylite, siderite, phosphoferrite, fairfieldite and apatite.[1]
References
External links
Media related to ludlamite at Wikimedia Commons
This article is issued from Wikipedia - version of the Saturday, October 31, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.