276 ECONOMIC GEOLOGY 



Uses. The metal is obtained in two forms, one amorphous, 

 the other crystalline. The former burns readily in the air, the 

 latter only at the high temperature of the oxyhydrogen flame. 

 The oxide, ZrO 2 , is the most important salt. It is reported to 

 have been used in the tile and pottery industries. The demand 

 for zircon is small. It has been supplied in the United States 

 by the intermittent working of the mines near Zirconia, N. C. 

 The crystals of Zircon are larger in Henderson County, where they 

 occur in pegmatites, than elsewhere when associated with 

 monazite. The crystals of zircon are larger also in the peg- 

 matites than they are in the granitic, gneissoid, or hornblendic 

 rocks. 



Only a few hundred pounds of zircon are obtained during an 

 entire year, and in some years there seems to be no recorded 

 output of the minerah 



Vanadium 



Properties. Vanadium, symbol V, is a rare element closely 

 allied to phosphorus. It acts both as an acid and a base. 

 The metal is permanent at ordinary temperatures, but is rapidly 

 oxidized to V 2 O 6 when heated. Its melting point is 1680 C.; 

 its specific gravity is 5.5, and its atomic weight is 51.2. 



Ores of Vanadium. Vanadinite, 3PbO, V 2 Os, PbCl 2 , is the 

 most common vanadium mineral. 



Descloizite, 4RO, V 2 O 5 , H 2 O. (R = Pb, Zn, in ratio 1:1.) 



Cuprodescloizite, 4RO, V 2 O 5 , H 2 O. (R = Pb, Zn, Cu.) 



Pucherite, Bi 2 Os, V 2 05, is a vanadate of bismuth. 



Mottramite is a vanadate of lead and copper. 



Carnotite is a vanadate of uranium and potassium of some 

 commercial significance where it occurs as canary yellow impreg- 

 nations in the sandstones of western Colorado and eastern Utah. 



Roscoelite is a vanadium silicate of the mica family, where 

 vanadium occurs displacing aluminum. The color ranges from 

 a clove-brown to a dark greenish-brown. 



There are many rare minerals bearing small percentages of 

 vanadium. These are most common in the ferromagnesian 

 rocks. They are present in the titaniferous magnetites, and in 

 rocks of nearly every class, whether of igneous or of sedimentary 

 origin. Vanadium has been observed in bauxite, cryolite, 

 rutile, peat, lignite, and in the ashes of wood. 



