OBDERX. OCTAHEDBAL COBALT-PYKITES. 453 



Fundamental form. Hexahedron. Vol. I. Fig. 1. 



Simple forms. H (r), Schladming, Stiria ; O (n), 

 Vol. I. Fig. 2., Schneeberg, Saxony; D (s). 

 Vol. I. Fig. 31. ; Ci (o), Vol. I. Fig. 34. 



Char of Comb. Tessular. 



Combinations. l.H.O.,Vol. I.Fig.3and4.Dobschau, 

 Hungary. 2. H. D. Fig. 151. 3. H. O. D. 

 4. H . O. D. C i . The three last from Schneeberg. 



Cleavage, traces in the direction of the octahedron, 

 the hexahedron and the dodecahedron, the first 

 sometimes a little more distinct. Fracture un- 

 even. Surface generally pretty smooth, the 

 faces of the hexahedron often curved. Subject 

 to tarnish. 



Lustre metallic. Colour tin-white, inclining to 

 steel-grey. . Streak greyish-black. 



Brittle. Hardness = 5-5. Sp. Gr. = 6-466, a 

 cleavable variety. 



Compound Varieties. Reticulated and some 

 other imitative shapes ; the individuals of them 

 being often discernible. Massive : composition 

 granular, individuals of various sizes, but general- 

 ly small and strongly connected. Fracture uneven 



OBSERVATIONS. 



1. According to STROMEYER, the octahedral Cobalt-py- 

 rites consists of 



Cobalt 20-31. 

 Arsenic 74-21. 

 Iron 3-42. 



Copper 0-15. 

 Sulphur 0-88. 



