Constituents of various Minerals. 271 



mon-stone obviously belongs to the second species, or it is com- 

 posed of 



1 atom silicate of alumina, 



1 atom silicate of lime. 



18. Marmolite. 



This mineral occurs in veins in the serpentine of Hoboken in 

 New Jersey, and in the same situation in the Bare Hills near 

 Baltimore. It was first described and named by Mr NUTALL. 



Its colour is pale green or greenish-grey. 



Texture foliated, with the laminae thin, and often parallel, as 

 in diallage. 



It cleaves parallel to the sides of an oblique and compressed 

 four-sided prism. 



Lustre pearly. Powder unctuous or shining. 



Translucent. 



Specific gravity, as determined in my laboratory, 2.410. Mr 

 NUTALL states it at 2.470. 



Before the blowpipe, it decrepitates, hardens, and slightly 

 exfoliates, without shewing any signs of fusion. 



Mr NUTALL analysed it, and found its constituents to be, 



Silica, 36 



Magnesia, 46 



Water, 15 



Lime, 2 



Protoxide of Iron and Chromium, . 0.5 



99.5 * 



* Sittimari's Journal, iv. 19- 



