21 



Perfectly opaque. 



Semihard. 



Brittle. 



Gives a yellowish brown streak. 



Heavy, in a moderate degree (4,500). 



' OBSERVATIONS. 



This fossil is readily distinguished from menacane, by 

 its stron<^er lustre and superior hardness, the colour of 

 the streak, and by its not being in the least magnetic; 

 which also sufficiently distinguishes it from iserme and 

 iron sand.* Being found in company with fragments of 

 rutile of a dark colour, the latter has by most been con- 

 founded under the same denomination; but the red colour 

 of the rutile, joined to its perfectly foliated fracture, with 

 a two-fold cleavage, intersecting each other at right an- 

 gles, and the thence resulting cubical fragments, distm- 

 guish it sufficiently from nigrine. 



° The present description is taken from a specimen I 

 h^iithe pleasure of receiving from Professor Jacquine the 

 younger, of Vienna. 



CHEMICAL CHARACTERS; 



The nigrine is infusible per se by the blow-pipe; but, 

 .with the ^assistance of borax, it melts to a transparent, hya- 

 cinth 



* Genuine iron sand must not be confounded .vith magnetic iron ore 

 ■ in'a^ s(inA/>rw, which usually passes under that name. 



