WOLFRAMITE, or WOLFRAM  , a mineral consisting of iron-manganese tungstate, (Fe, Mn)WO4 . The name is of doubtful origin, but it has been assumed that it is derived from the German Wolf and Rahm (froth), corresponding with the spuma lupi of old writers, a term hardly appropriate, however, to the mineral in question . Wolframite crystallizes in the monoclinic system, with approximation to an orthorhombic type; and the crystals offer perfect pinacoidal cleavage . The colour of wolframite is generally dark brownish-black, the lustre metallic or adamantine, the hardness 5 to 5.5, and the specific gravity 7.1 to 7.5 . Wolframite may be regarded as an isomorphous mixture, in variable ratio, of iron and manganese tungstates, sometimes with a small proportion of niobic and tantalic acids . It was in wolframite that the metal tungsten was first recognized in 1785 by two brothers, J . J. and F. d'Elhuyar . At the present time the mineral is used in the manufacture of tungsten-steel and in the preparation of certain tungstates . Wolframite is commonly associated with tin-ores, as in many parts of Cornwall, Saxony and Bohemia . In consequence of the two minerals, cassiterite and wolframite, having nearly the same density, their separation becomes difficult by the ordinary processes of ore-dressing, but may be effected by means of magnetic separators, the wolf ramite being attracted by powerful magnets . A process introduced many years ago by R . Oxland consisted in roasting the mixed ore with carbonate of soda, when the wolfram was converted into sodium tungstate, which was easily removed as a soluble salt .

Wolf ramite occurs at many localities in the

United States, notably at Trumbull, Conn., where it has been mined, and at Monroe, Conn., where it accompanies bismuth ores . Other localities are in Mecklenburg county, N.C., and in the Mammoth mining district, Nevada . Wolframite has in some cases resulted from the alteration of scheelite (q.v.), though on the contrary pseudomorphs are known in which scheelite has taken the form of wolframite . By oxidation wolframite may become encrusted with tungstic ochre, or tungstite, sometimes known as wolframine, a name to be carefully distinguished from wolf ramite . As the relative proportions of iron and manganese vary in wolframite, the composition tends towards that of other minerals . Thus there is a manganous tungstate (MnWO4) known as hi bnerite, a name given by E . N . Riotte, in 1865, in compliment to Adolph Hiibner, a Saxon mineralogist . There is also a mineral which contains little more than ferrous tungstate (FeWO4), and is known as ferberite, having been named by A . Breithaupt in 1863 after Rudolph Ferber . The original hiibnerite came from the Mammoth district, Nevada, and the ferberite from the Sierra Almagrera in Spain . It is possible that such minerals may represent the extreme terms in the series formed by the varieties of wolframite .

(F . W .