244 METALS. 



Brittle. H=5— 6. Gr=5-3— 6'4. American 5-3— 5*71. 

 Bavarian 5 7 — 6 4. 



Composition of an American specimen ; columbiG acid 

 79*6, protoxyd of iron 164, protoxyd of manganese 4*4, oxyd 

 of tin 0*5, oxyds of copper and lead O'l. The Bavarian 

 columbite, besides having a higher specific gravity than the 

 American, has also a black streak. Damour has proposed 

 for it the name Baierine ; but the differences, as far as yet 

 known, are not important. 



Infusible alone before the blowpipe. With borax in a fine 

 powder fuses quite slowly, but perfectly, to a dark green glass, 

 which indicates only the presence of iron. 



Dif. Its dark color, submetallic luster, and a slight iri- 

 descence, together with its breaking readily into angular 

 fragments, will generally distinguish this species from the 

 ores it resembles. 



Obs. Occurs in granite at Bodenmais in Bavaria, and 

 also in Bohemia. In the United States, it is found in the 

 same rocks, feldspathic or albitic, at Middletown and Had- 

 dam, Conn. ; at Chesterfield and Beverly, Mass., and at 

 Acworth, N. H. A crystal was found at Middletown, which 

 originally weighed 14 pounds avoirdupois ; and a part of it, 

 6 inches in length and breadth, weighing 6 lbs. 12 oz., is now 

 in the collections of the Wesleyan University of that place. 



This mineral was first made known from American speci- 

 mens, by Mr. Hatchett, an English chemist, and the new 

 metal it was found to contain was named by him columbium. 



Tantolite or Ferrotantalite. This is an allied mineral, often called, 

 from its locality at Kimito in Finland, kimito-tantalite. It is a neutral 

 tantalate of iron. H=5 — 6. Gr=72 — 8*0. A variety from Broddbo 

 contains 8 per cent, of oxyd of tin, with 6 of tungstic acid. Sp. gr. 

 =65. 



Note. — The metal named Columbium by Hatchett, is the same that 

 has since been called Niobium ; and the Tantalum of the Swedish ores 

 is a different metal. For other ores of columbium and tantalum, see 

 pages 208, 209. 



wolfram. — Tungstate of Iron and Manganese. 



Trimetric. In modified rhombic or rectangular prisms ; 

 sometimes pseudomorphous in octahedrons imitative of tung- 

 state of lime. Also massive. Color dark grayish-black ; 



Of what does columbite consist ? How does it differ from other ores ? 

 Describe wolfram. 



