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Befanamo pegmatite, Anjozorobe District, Ankazobe Pegmatite Field, Analamanga Region, Antananarivo Province, Madagascar

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(Befanamo, Distrikan'i Anjozorobe, Pegmatitan' i Ankazobe, Faritra Analamanga, Faritra Analamanga, Faritanin'i Antananarivo, Madagasikara)

A granite NYF pegmatite, Monazite-Thortveitite subtype that is hosted in an amphibolite-gneis. This scandium-rich pegmatite has produced more than 40 kg of "befanamite" (Y-Free variety of thortveitite) since its discovery in 1908 (especially in the early 1950s). It is situated 2 km W of the village Ambalabako, about 20 NE of Ambatomanoina, and about 80 km N of the capitol Antananarivo.
"Befanamite" was first described from this locality. It was discovered in the eluvials of the pegmatite in 1918 by J. B. Rasamoel.



References:
- Guigues, J. (1955): Etude des gisements de pegmatite de Madagascar (Deuxième partie). Travaux du Bureau Géologiques de Madagascar 67, Service Geologique, Tananarive, p 6-8

- Behier, J. (1960): Contribution á la mineralogie de Madagascar. Annales Géologiques de Madagascar XXIX, Tananarive, 19-20 [on befanamite]

- Pezzotta, F. (1999): Madagaskar. Das Paradies der Mineralien und Edelsteine. ExtraLapis nr 17, 44-46 [german version, a short notice]




Group 4 - Oxides and Hydroxides
  		• Columbite-(Fe)4.DB.35
    FeNb
     
    2
    		O
     
    6
  		• Euxenite-(Y)4.DG.05
    (Y,Ca,Ce,U,Th)(Nb,Ta,Ti)
     
    2
    		O
     
    6
  		• Hematite4.CB.05
    Fe
     
    2
    		O
     
    3
  		• Ilmenite4.CB.05
    Fe
    2+
     
    		TiO
     
    3
  		• Magnetite4.BB.05
    Fe
    2+
     
    		Fe
    3+
    2
    		O
     
    4
  		• Quartz4.DA.05
    SiO
     
    2
  		• Rutile
    var: Strüverite    		4.DB.05
    (Ti,Ta,Fe)O
     
    2
  		• Samarskite-(Y)4.DB.25
    (Y,Fe
    3+
     
    		,Fe
    2+
     
    		,U,Th,Ca)
     
    2
    		(Nb,Ta)
     
    2
    		O
     
    8
    Group 7 - Sulphates, Chromates, Molybdates and Tungstates
  		• Fergusonite-(Y)7.GA.05
    YNbO
     
    4
    Group 8 - Phosphates, Arsenates and Vanadates
  		• Xenotime-(Y)8.AD.35
    YPO
     
    4
    Group 9 - Silicates
  		• Beryl9.CJ.05
    Be
     
    3
    		Al
     
    2
    		Si
     
    6
    		O
     
    18
  		• Biotite9..
  		• Microcline9.FA.30
    K[AlSi
     
    3
    		O
     
    8
    		]
  		• Muscovite9.EC.15
    KAl
     
    2
    		[(OH)
     
    2
    		|AlSi
     
    3
    		O
     
    10
    		]
      var: Gilbertite9.EC.15
    KAl
     
    2
    		[(OH)
     
    2
    		|AlSi
     
    3
    		O
     
    10
    		]
  		• Schorl9.CK.05
    [Na][Fe
    2+
    3
    		][Al
     
    6
    		][(OH)
     
    3
    		|OH|(BO
     
    3
    		)
     
    3
    		|Si
     
    6
    		O
     
    18
    		]
  		• Spessartine9.AD.25
    Mn
    2+
    3
    		Al
     
    2
    		[SiO
     
    4
    		]
     
    3
  		• Thortveitite9.BC.05
    (Sc,Y)
     
    2
    		[Si
     
    2
    		O
     
    7
    		]
  		• Vermiculite9.EC.50
    (Mg,Fe,Al)
     
    3
    		(Al,Si)
     
    4
    		O
     
    10
    		(OH)
     
    2
    		·4H
     
    2
    		O
  		• Zircon9.AD.30
    Zr[SiO
     
    4
    		]
      var: Malacon9.AD.30
    Zr[SiO
     
    4
    		]
    Unclassified Minerals
  		• 'Bastnäsite'-
  		• Befanamite-
    Sc
     
    2
    		Si
     
    2
    		O
     
    7
  		• 'Columbite-Tantalite'-
  		• 'Monazite'-
  		• 'Perthite'-


    26 entries listed. 20 valid minerals.

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