IRON. 183 
Wolframite.—Wolfram. Iron-Manganese Tungstate. 
Monoclinic. Sometimes pseudomorphous in octahedrons 
formed by the alteration of tungstate of lime. Also massive. 
Color dark grayish-black ; streak dark reddish-brown. 
Lustre submetallic, shining, or ‘dull. it = 0-dy Os 
71-75. 
Composition. (Fe,Mn)O,W. A typical variety affords 
tungsten trioxide 76°47, iron protoxide 9°49, manganese 
protoxide 14:04=100. A manganese wolframite has been 
named Hiibnerite. B.B. fuses easily to a magnetic globule ; 
with aqua regia dissolved with the separation of yellow 
tungsten trioxide. 
Found often with tin ores. Occurs in ese and at 
Zinnwald and elsewhere in Europe. In the United States it 
is found at Monroe and Trumbull, Conn.; on Camdage 
Farm, near Blue Hill Bay, Me.; near Mine ‘la Motte, Mis- 
sourl ; in the gold regions of North Carolina; in Mammoth 
Mining district, Nevada Hiibnerite. 
Colum bite. 
Trimetric. In rectangular prisms, more or less modified. 
Also massive. Cleavage parallel to 
the lateral faces of the prism, some- 
what distinct. 
Color iron-black, brownish-black ; 
often with a characteristic iridescence 
on a surface of fracture; streak dark 
brown, slightly reddish. Lustre sub- 
metallic, shining. Opaque. Brittle. 
H.=5-6. G.=5:'4-6'5. 
Composition. - Iron columbate, of 
the formula F O; Cb,=Columbium 
pentoxide 79°6, iron protoxide 16:4, 
manganese protoxide 4-4, tin oxide 05, lead and copper 
oxides 01—100. Tantalum often replaces part of the 
columbium, and in this case the mineral is of higher speci- 
fic gravity. B.B. alone infusible. It imparts to the borax 
bead the yellow color of iron. 
Diff. Its dark color, submetallic lustre, and a slight ivi- 
descence, together with its breaking readily into angular 
fragments, will generally distinguish this species from the 
ores it resembles. 

