PHYSIOGRAPHY. 81 



Nephrite Nickel Glance. 



Color green, particularly leek-green ; rarely with a shade 

 f blue, and still more so, with red, passing into grey and 

 white. Translucent . . . translucent on the edges. 

 Very tough. Hardness =6-0 . . . 7-0. Sp. gr. =2*932 

 ,.3-024. 



1. Alone before the blowpipe, it is infusible, but becomes white. 

 2. Analysis. 



By KASTITER. By BOWEN, 



from Srnithfield, (R. I.) 



Silica - - - 50-50 - - 44-688 



Magnesia - - - 31-00 - - 34-631 

 Alumina - - - 10-00 - - -562 



Oxide of iron - - - 5-50 - - 1747 



Oxide of chrome - - 005 Lime - 4-250 



Water 275 - - 13-417 



The excess of volatile matter in the variety from Srnithfield is proba- 

 bly owing to its intermixture with Calcareous Spar, in which it is im- 

 bedded. 



3. It is brought from China and Egypt. A large block was found hi 

 the alluvial soil of the alum-earth mines at Schwemmsal in Saxony. 



A very handsome sky-blue variety is found in the white primitive 

 limestone of Smithfield, (R. I.) and a greenish and reddish-grey variety, 

 under similar circumstances, at Easton, (Penn.) 



NICKEL GLANCE. Euotomous Eruthleucone- 

 Pyrites. 



Primary form. Cube. 



Secondary form. Cube, with angles truncated. 



Cleavage, highly perfect, parallel with the primary form. 



Lustre metallic. Color silver-white . . . steel-grey. 



Hardness =5-5. Sp. gr. =6-097 . . . 6-129. 



Compound Varieties. Massive : composition lamellar 

 and granular. 



1. Alone, in a mattrass, it decrepitates strongly, affording, at a red 

 heat, sulphuret of arsenic, then sublimes as a transparent, yellowish- 



