THE NONMETALLIC MINERALS. 



355 



counties, North Carolinii. The mineral has also been found in the form 

 of black o-rains and pebbles, sometimes weij^hino- one-fourth of an ounce, 

 in thegokl-bi^aring sands of Rutherford County. At the Wiseman Mine 

 large masses, one weighing upwards of 20 pounds, were found some 

 years ago. The analyses quoted above were made from material from 

 this mine,* 



Uses. — See under Monazite, p. 383. 



4. Wolframite and Hijbnerite. 



Composition, a tungstate of manganese, and iron. The proportion of 

 the iron and manganese are quite variable, the tungsten remaining 

 nearly constant. The name hiibnerite is given to the variety contain- 

 ing very little iron, but consisting essentially of tungsten and man- 

 ganese. The following table shows the range in composition: 



Wolframite is dark reddish brown to black in color, with a resinous 

 luster; has a hardness of about 5, a specific gravity of 7.55, and a pro- 

 nounced tendency to cleave with flat, even surfaces. Its great weight, 

 color, and cleavage tendencies are strongly marked characteristics, and 

 the mineral once identified is as a rule easily recognized. 



Occurrence. — The mineral is found in veins associated with tin ore 

 (cassiterite), and also with quartz, pyrite, galena, sphalerite, etc. The 

 chief known localities in the United States are Monroe and Trumbull, 

 Connecticut; Blue Hill Bay, Maine; Rockbridge County, Virginia 

 (Specimen No. 65206, U.S.N.M.); the Mammoth district, Nye and 

 Lander counties, Nevada (Specimens Nos. 15755, 5653, U.S.N.M.);Black 

 Hills, S. Dakota (Hiibnerite) (Specimen No. 53461, U.S.N.M.); Bonita 

 and W^hite Oaks, Lincoln County, New Mexico; Falls County, Texas 

 (Specimen No. 62766, U.S.N.M.); Russellville, Arizona (Specimen No. 

 53223,U. S. N. M. ). The foreign localities are the tin regions of Bohemia, 

 Saxony (Specimen No. 67752, U.S.N.M.), and Cornwall and Devon- 

 shire (Specimens Nos. 67460, 67753, 67787, and 67788, U.S.N.M.), 

 England; also Australia (Specimens Nos. 60978, 60967, U.S.N.M.)and 

 Bolivia and Peru, South America. For uses, see under Scheelite, 

 •p. 356. 



^See the Minerals of North Carohna, Bulletin 74, U. S. Geological Survey, 1891. 



