Alluaudite

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Alluaudite
Alluaudite 2 Sodium iron manganese phosphate Pleasant Valley Mine near Fourmile Custer County South Dakota 2264Spp.jpg
Alluaudite
General
Category Phosphate minerals
Formula
(repeating unit)
(Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3
Strunz classification 08.AC.10
Dana classification 38.2.3.6
Identification
Color Dirty yellow to brownish yellow, grayish green; superficially dull greenish black, brownish black, black, when altered
Crystal system Monoclinic
Cleavage Distinct/ good
On {100} and {010} {110}, good
Mohs scale hardness 5½ - 6
Streak Brownish yellow
Diaphaneity Translucent
Density 3.4 - 3.5 g/cm3

Alluaudite is a relatively common alkaline manganese iron phosphate mineral with formula (Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3, of secondary (metasomatic) origin, related with granitic pegmatites mainly. Named by Alexis Damour in 1847 after François Alluaud (II) (1778–1866).[1][2]

References[edit]

  1. ^ http://www.mindat.org/min-142.html Mindat
  2. ^ http://www.handbookofmineralogy.org/pdfs/alluaudite.pdf Handbook of Mineralogy