42 Mr Haidinger on the Crystalline Forms 



Simple forms contained in the combinations which were ob- 

 served among the crystals of the variety analyzed. 



Combinations. 1. (f P — 2) 5 . ( |P^— l )-. (p ^ 3 p + } 



P + oo • (Pr + oo ) 5 . (Pr + oo ) 3 . Fig 2. 



The 3d figure represents the projection upon P — on , the 

 4th figure the elevation upon a plane parallel to the short dia- 

 gonal of the prism P + oo . The hemi-prismatic character of 

 the species appears only in the disposition of the faces marked 



c. They form horizontal edges of combination with (Pr) 3 . 

 The edges between (f P — 2) 5 and P -f 1 are parallel to 



those between P + 1 and (Pr -f 00 ) 3 . These crystals are 

 from two to three lines in thickness, and some of them nearly 

 an inch long:. 



2. Pr. (Pr— l) 3 . Pr. P. P+l. P + oo- (Pr + oo y. 



(Pr + 00 ) 3 . (Pr 4 00 )\ Fig. 5. 



Small, but very well pronounced crystals of this variety 

 were disengaged from the same specimen which contains the 

 variety 1. They were found in small drusy cavities, which 

 were discovered when the whole was broken up for analysis. 

 The faces of Pr, marked e in the figure, have not been de- 

 scribed ; they are rarely observed in the crystals of this species. 



Cleavage, Pr-fao highly perfect and easily obtained ; P+oo 

 also perfect, but less easily obtained ; traces of Pr+ 00 , and of 



