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Download hereGENERAL DESCRIPTION
Mangano-neptunite is the manganesian end-member of neptunite (Na2 K Li (Fe2+, Mn2+)2 Ti2 [ Si8O24 ]). Neptunite is a potassium, sodium, lithium and titanium silicate.
Its crystals are prismatic and are sometimes elongated. Usually, they are pyramidal. Mangano-neptunite is transparent, of pink-orange to red-cherry colour, with a vitreous luster. It is often associated to aegirine, natrolite or analcime.
The deposits are very few: the quarry Point of Rocks in New Mexico, USA; Range of Khibiny, Kola Peninsula, Russia; the mount Malosa, Malawi and the quarry Poudrette, Mont Saint-Hilaire, Québec.
The conservation location of the type of this species (originating in the Mounts Maly Mannepakhk (Malyi Mannepakhk) in the Khibiny range, Kola peninsula, Murmanskaja Oblast', Russia) is unknown.
HISTORY : Name from the Roman mythology : Neptune, the Roman God of the Sea and its manganoan composition
Species first described in 1923 par Kurbatov, Russian mineralogist
Type-locality : Mount Maly Mannepakhk, Kola Peninsula, Russia
CHEMICAL FORMULA : Na2 K Li (Mn2+, Fe2+)2 Ti2 [Si8O24]
CRYSTAL SYSTEM : Monoclinic
COLOR : Orange, cherry-red
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous to resineous
STREAK : Red-brownish
MORPHOLOGIE : Prismatic crystals often elongated
HARDNESS : 5,0-6,0
CHEMICAL CLASS: 3,26
DENSITY : VIII - Silicates
GROUP : Neptunite series
STRUNZ CLASS BEFORE 2001 : 8/F.37-20
STRUNZ CLASS AFTER 2001 : 9.EH.05
