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Formula: Fe2+(WO4)
Anhydrous tungstate,
wolframite group, a complete solid solution exists between
ferberite and
hübnerite.
Crystal System: Monoclinic
Specific gravity: 7.58 measured, 7.6 calculated
Hardness: 4 to 4½
Streak: Black to brownish-black
Colour: Black
Solubility: Easily fusible. Slowly decomposed by hot concentrated sulphuric or hydrochloric acid. Decomposed by aqua
regia with the separation of tungstic oxide.
Common impurities: Nb,Ta,Sc,Sn
Environments:
Pegmatites
Sedimentary environments
Metamorphic environments
Hydrothermal environments
Ferberite occurs in hydrothermal veins, medium temperature metamorphic rocks and
granitic pegmatites immediately
associated with granitic intrusive rocks; it also occurs in alluvial
and residual deposits.
In high temperature (hypothermal) hydrothermal veins it is associated with
cassiterite, arsenopyrite,
apatite, tourmaline,
topaz, fluorite, specular
hematite, molybdenite and
bismuth. In moderate temperature (mesothermal) veins it is associated with
cassiterite and sulphides, scheelite,
bismuthinite and siderite
(Dana).
Localities
At Rumsby's mine, New South Wales, Australia, ferberite is the main ore mineral, associated with a
granite intrusion, and it
is commmonly intergrown with
bismuth, arsenopyrite and
fluorite. Some ferberite has altered to
secondary
scheelite.
AJM 18.2.26
At the Yaogangxian Mine, Yaogangxian W-Sn ore field, Yizhang County, Chenzhou, Hunan, China, ferberite occurs as fine
opaque, black, lustrous crystals, striated lengthwise, and sometimes associated with
muscovite and fluorite
(AESS).
Ferberite from Yaogangxian - Image
At Long Hill, Haddam, Middlesex county, Connecticut, USA, ferberite
pseudomorphs after scheelite
have been found
(KL p215).
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