Discovery of Columbite in Chesterfield, Mass. 221 



Cleavage, parallel with M, quite perfect; in other direc- 

 tions uneven. Lateral planes vertically streaked. 



Lustre, shining, sub-metallic. Color, iron black. Tar- 

 nished upon the cleavage planes, mostly blue. Streak, brown- 

 ish black: powder, chocolate brown : opake. 



Hardness. Scratches glass. Brittle. 



Specific gravity, 6*00. 



Chemical Examination, 



Alone before the blowpipe, in very thin fragments, it be- 

 comes rounded upon the edges, and assumes a glossy black 

 color; but is not taken up by the magnet, even when redu- 

 ced to powder. When pulverized, it enters into fusion along 

 with borax, to which it communicates a faint bottle green 

 stain : with phosphate of ammonia and soda, it also dissolves, 

 affording a lemon yellow glass, which on cooling, becomes 

 clouded and fades to a cream color. 



Digested, in the state of an impalpable powder, with nitro- 

 muriatic acid, it offered no signs of decomposition. 



1. After having tried to effect its decomposition, by ignit- 

 ing it alone, first with potash and then with carbonate of soda, 

 neither of which succeeded perfectly, I employed a mixture 

 of five parts of carbonate of soda, and two of calcined borax. 

 This process proved nearly effectual; and by the addition of 

 two parts of nitrate of potash to the same proportions, in a 

 succeeding trial, the whole of the mineral employed was 

 decomposed. 



2. The fused mass indicated manganese by an intense 

 green color, which it communicated to the water, added 

 to effect its separation from the crucible. With muriatic 

 acid the green color passed to a red, and finally to a rich lem- 

 on yellow; at the same time, occasioning an abundant white 

 precipitate. 



3. The muriatic solution, (2.) separated from its insoluble 

 precipitate, was digested with nitric acid ; and a part of it de- 

 composed by j)Otash in excess, and the solution boiled for a 

 few moments upon its precipitate. 



4. To the alkaline liquor, (3.) separated by the filter from 

 its precipitate, was added muriatic acid, and through the so- 

 lution a stream of sulphuretted hydrogen passed ; a copious 

 orange colored precipitate made its appearance, and imme- 

 diately settled to the bottom. The precipitate was collected 

 on a filter, dried, and exposed upon charcoal to the intense 



