Ludlamite
(Fe,Mn,Mg)3(PO4)2·4H2OIMA symbol Lud[1] Strunz classification 8.CD.20 Crystal system Monoclinic Crystal class Prismatic (2/m)
(same H-M symbol) Space group P21/a Unit cell a = 10.541(5), b = 4.646(4)
c = 9.324(5) [Å]; β = 100.52°; Z = 2 Identification Color Apple-green to bright green Crystal habit Tabular crystals; massive, granular 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 [2][3][4]
(same H-M symbol)
c = 9.324(5) [Å]; β = 100.52°; Z = 2
Ludlamite is a rare phosphate mineral with chemical 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.[4] It occurs associated with whitlockite, vivianite, triploidite, triplite, triphylite, siderite, phosphoferrite, fairfieldite and apatite.[2]
References
External links
Media related to ludlamite at Wikimedia Commons
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