ORDER VII. 1'UISMATIC AXINITE. 34-3 



lei to their edges of combination. In general 

 they are smooth and shining. 



Lustre vitreous. Colo r clove-brown, various 

 shades inclining to plum-blue and pearl-grey. 

 Green from an admixture of Chlorite. Streak 

 white. Transparent ... translucent, sometimes 

 only on the edges. The deepest shades of violet- 

 blue tints appear if the mineral is viewed in the 

 direction perpendicular to Pr + oo (r). 



Hardness = 6-5 ... 7-0. Sp. Gr. = 3-271, the 

 crystallised variety from Cornwall. 



Compound Varieties. Massive : composition la- 

 mellar, generally a little bent ; faces of composi- 

 tion irregularly streaked. Sometimes the composi- 

 tion is granular and impalpable. 



OBSERVATIONS. 



1. From the angles given by HAUY, the inclination of 

 the axis in the plane of the long diagonal would be == 8', 

 and in the plane of the short diagonal = 8 13'. He 



considers as the primitive form the combination of -- - 



2 



aficl r I L_-Z-_, supposing at the same time the trans- 



verse section of (Pr + ac) 3 , to be = 90% the inclination of 



_L^nr^^!also = 90%andonj(lI^): = 78 

 22 2 



27' 47". These quantities, however, should be first ex- 

 actly ascertained, before, on account of their very simplici- 

 ty, they be adopted as the effective dimensions of the 

 forms, as there is nothing in experience which confirms the 

 existence of such simple relations. The incidences of the 

 faces, and the plane angles are, according to HAUY, 



