OEDER VIII. PRISMATIC IRCN-ORE. 411 



= 117 3(y, of n on M = 117 50% according to 

 PHILLIPS, n on n over M = 130 14', according 

 to BROOKE. 



Cleavage, pretty distinct, parallel to the broad 

 faces of the crystals. Surface, deeply streaked 

 in a longitudinal direction. 



Lustre adamantine. Colour, various brown shades, 

 of which yellowish-brown, hair-brown, clove- 

 brown, and blackish- brown, are the most com- 

 mon. Streak yellowish-brown. Crystals often 

 semi-transparent, and shewing a blood-red tint. 

 Other varieties are nearly opake. 

 Brittle. No action on the magnet. Hardness 

 = 5-0 ... 5-5. Sp. Gr. = 3-922, of a columnar 

 compound variety. 



Compound Varieties. Globular, reniform, stalac- 

 titic and fruticose shapes : surface of various de- 

 scriptions, smooth, granulated, reniform, drusy; 

 composition columnar, individuals very delicate, 

 often impalpable. In the latter case fracture be- 

 comes even, flat conchoidal or uneven. The com- 

 position is often repeated ; granular and curved la- 

 mellar masses are formed of columnar composi- 

 tions, the faces of composition being either smooth, 

 or covered with reniform asperities. Massive : com- 

 position columnar or impalpable. Sometimes the 

 particles are so slightly coherent, that the mass ap- 

 pears earthy and dull. Pseudomorphoscs of rhom- 

 boheclral Lime-haloide. 



