270 PHYSIOGRAPHY. CLASS II. 



Lustre vitreous, inclining to resinous. Colour 

 green, often inclining to brown, and passing into 

 grey and white, and also into black. Streak 

 white . . . grey, corresponding to the colour. 

 Faintly transparent ... opake. 

 Brittle. Hardness rrs 5-0... 6-0. Sp. Gr = 3-349 

 an ash-grey variety ; 3.327 Omphazite from 

 the Saualpe ; = 3-327 Fassaite ; 3-274 a greyish- 

 white variety compound in laminae parallel to 

 Pr + oo ; = 3-233 a grass-green variety from the 

 Bacher mountain in Lower Stiria. 

 Compound Varieties. Twin-crystals : face of 

 composition parallel, axis of revolution perpendicu- 

 lar to ?r -f- oo. Sometimes crystals of this kind are 

 in cruciform aggregations. Massive varieties com- 

 pound in the direction of , as in Sahlite ; this 

 must not be taken for cleavage, as it does not con- 

 tinue throughout the whole mass, but only produces 

 more or less thick laminae, often separated from 

 each other by some extraneous substance : it often 

 possesses a slight pearly lustre: there is also composi- 

 tion parallel to Pr -f oo, as in Mussite. Massive : 

 composition granular of various sizes of individuals, 

 often but slightly cohering, but often also very inti- 

 mately connected ; faces of composition rough. The 

 individuals of lamellar and columnar varieties are 

 in most cases easily separated, and present striated 

 faces of composition. 



OBSERVATIONS. 



1. According to the measurements of Mr BROOKE and- 



