382 PHYSIOGRAPHY. ctASS ir. 



(r) Vol. I. Fig. 31. ; A*, Vol. 1. Fig. 32. ; B, 

 Vol. I. Fig. 33.; Ci, Vol. I. Fig. 34. ; Ti, 

 Vol. I. Fig. 35. 



Char, of Comb. Tessular. 



Combinations. 1. H. O. Vol. I. Fig. 3 and 4. 

 2. H. D. Fig. 151. 3. H. O. D. 4. H. O. D. B. 

 Fig. 155. 5.HO.D.C*. 6.H.O.D.A.B.Ci.Ti. 



Cleavage, octahedron, with smooth faces, but very 

 much interrupted. Fracture conchoidal, uneven. 

 Surface generally very smooth and shining, and 

 everywhere the same. 



Lustre adamantine, sometimes metallic adamantine 

 or imperfect metallic. Colour between cochineal- 

 red and lead-grey ; also pure cochineal-red, and 

 in capillary crystals almost carmine-red. Streak 

 several shades of brownish-red, shining. Semi- 

 transparent ... translucent on the edges. 



Brittle. Hardness = 3-5 ... 4-0. Sp. Gr. 5 992, 

 crystals from Chessy. 



Compound Varieties. Massive : composition gra- 

 nular, individuals of various sizes, or even impal- 

 pable. In the latter case, fracture becomes flat 

 conchoidal or even, the surface of the fracture glim- 

 mering. Sometimes earthy. 



OBSERVATIONS. 



1. Those varieties which consist of friable particles, and 

 present an earthy fracture, and which are besides often 

 mixed with oxide of iron, or several Malachites, &c., con- 

 stitute the Tilc-orc, which was formerly considered as a par- 

 ticular species, and divided into earthy and indurated Tile- 



