MINERAL from GREENLAND. 391 



Translucent. 



Hardness equal to that of felfpar. Iron fcratches it with 

 difficulty. 



Brittle. 



Easily frangible. 



Specific gravity, at the temperature of 6o°, 2.378. The 

 fpecimen was not abfolutely free from fahlite. 



When heated to rednefs, does not decrepitate, nor fall to 

 powder, but becomes dark-grey, and aflumes very nearly the 

 appearance of the Swedifh natrolite of Mr Allan, which I 

 confider as fettftein. If any particles of fahlite be mixed with 

 it, they become very confpicuous, by acquiring a white colour, 

 and the opacity and appearance of chalk. The lofs of weight 

 was 2.1 per cent. I was not able to melt it before the blow- 

 pipe. 



II. Chemical analysis. 



1. A hundred grains of the mineral, reduced to a fine pow- 

 der, were mixed with 200 grains of pure foda, and expofed for 

 an hour to a ftrong red heat, in a platinum crucible. The mix- 

 ture melted, and afTumed, when cold, a beautiful grafs-green 

 colour. When foftened with water, the portion adhering to 

 the fides of the crucible acquired a fine brownifh-yellow. Ni- 

 tric acid being poured upon it, a complete folution was ob- 

 tained. 



2. Suspecting, from the appearance which the fufed mafs 

 afTumed, that it might contain chromium, I neutral ifed the fo- 

 lution, as nearly as poflible, with ammonia, and then poured 

 into it a recently prepared nitrate of mercury. A white preci- 

 pitate fell, which being dried, and expofed to a heat rather un- 

 der rednefs, was all diflipated, except a fmall portion of grey 



matter, 



