292 UNIVERSITY OF VIRGINIA PUBLICATIONS 



uses, and in Rontgen ray therapy it is used in place of bismuth nitrate, 

 which has sometimes given bad effects. Zirconia is a beautiful soft white 

 powder which is well adapted for making paints and lacquers, as it is 

 unaffected by gases, acids, or alkalies, and has good covering power. It 

 makes a good opaque glass, but for this use the borate is better than the 

 oxide. It is used for a polishing powder in place of tin oxide. Ferrozir- 

 conium is manufactured by one German firm for use in steel. Zirconium 

 carbide is extremely hard and makes a valuable abrasive. Glass 7 mm. 

 (J-inch) thick is cut with it as readily as with a diamond. 



Clear zircons of brownish, orange, or reddish color are cut for gems and 

 "are then known as hyacinths. There is no probability of stones sufficiently 

 large for cutting being found at the Ashland locality, but they may be 

 present in some of the pegmatites of the crystalline area. 



