Anhydrous tungstate, a complete solid solution exists between ferberite and hübnerite.
Specific gravity: 7.51
Hardness: 4 to 4½
Streak: Black to brownish-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
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).
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 Long Hill, Haddam, Middlesex county, Connecticut, USA, ferberite pseudomorphs after scheelite have been found (KL p215).
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