ORDEEXIH. HEMI-FRISMATIC SULPHUR. 51 



(Pr + oc) 5 P r + oo. Pr + oo. Fig. 184. 

 All of them from Nagyag, Transylvania. 



Pr 

 Cleavage, and Pr -f- oo rather perfect ; less 



distinct _, P -f oo and f r -f OD ; traces of 



(Pr -f oo) 3 ; all of them much interrupted. Frac- 

 ture perfect conchoidal. Surface, the prisms in 

 the direction of the principal axis streaked paral- 

 lel to that line, the inclined faces often rough, 



p jp r 



particularly , and almost always _ and 



___; is sometimes streaked parallel 

 2 2 



P 



to the edges of combination with ^. 



Lustre resinous. Colour, aurora-red, several shades, 

 little differing from each other. Streak orange- 

 yellow ... aurora-red. 



Sectile. Hardness = 1 -5 ... 2-0. Sp. Gr. = 3-556, 

 a semi-transparent crystal. 



Compound Varieties. Massive: composition gra- 

 nular, of various sizes of individuals, strongly con- 

 nected. Fracture conchoidal, uneven. 



OBSERVATIONS. 



1. According to KLAPROTH and LAUGIER, hemi-prisma- 

 tic Sulphur consists of 4 



Sulphur 31-00 30-43. 



Arsenic 69-00 69-57. 



Its chemical formula is As S 2 , which requires 29-96 of sul- 



