274 ECONOMIC GEOLOGY 



Geographical Distribution. There are three belts of titanium- 

 bearing rocks in the United States: (1) The Appalachain belt. 

 The maximum development occurs, as above noted, in Nelson 

 Co., Virginia. In Chester, Pa., rutile occurs in exceptionally 

 pure crystals, which have brought high prices for the dental trade 

 and for museum specimens. It occurs in New York, where large 

 quantities of titaniferous iron abound, and in Vermont, where 

 many fine crystals of rutile have been obtained. (2) The North- 

 ern Belt, where titaniferous ores have been mined in Minnesota 

 in considerable quantity. (3) In Wyoming, where the ore is 

 similar to that found in Minnesota. 



In foreign countries rutile is found in Norway, South Australia, 

 and Queensland. 



Geological Horizon. Titanium minerals are more abundant 

 with the pre-Cambrian, Cambrian, and Ordovician terranes than 

 with the later geological formations. 



Uses. The most important use of titanium is in the manufac- 

 ture of steel and cast-iron, to which it imparts hardness and 

 toughness. The alloy ferro-titanium, containing 10 to 20 per 

 cent, of titanium, is first manufactured. This is added to the 

 molten iron so as to produce a steel bearing 0.1 per cent, titanium. 

 Steel rails thus formed resist the wear of heavy traffic much longer 

 than ordinary rails. Titanium-thermit is another form in which 

 titanium is introduced into steel. Cupro-titanium is an alloy of 

 titanium used in the manufacture of bronze and other castings 

 containing copper. Titanium is used in the manufacture of 

 electrodes for arc-lights. The chloride of titanium, TiCl 2 , is 

 used in dyeing. The sulphate, Ti 2 (S04)3, is used both as a 

 striper and a mordant. The titanous potassium oxalate is used 

 as a yellow dye and a mordant in the treatment of leather. 

 Ti(SO4)a is used in the detection of fluorine. The tile industry 

 also utilizes rutile. . It gives a soft, beautiful yellow color in tile 

 and brick. Rutile is also used to give to artificial teeth an ivory 

 tint. The nitride of titanium is sometimes formed in smelting 

 titaniferous iron ores. This compound has commercial possi- 

 bilities as a fertilizer. Rutile finds some use as a gem. 



ZIRCONIUM 



Properties. Zirconium, symbol Zr, is a rare element closely 

 allied to titanium. Its melting point is 1500 C ; its specific grav- 

 ity is 4.15, and its atomic weight is 90.6. 



