314 Notice of Warwickite. 



the vicinity of the first, in which several forms half an inch in 

 diameter have occurred, although the last discovered crystals are 

 wanting in lustre when compared with those first mentioned y 

 and are moreover in a somewhat decomposing condition. They 

 are associated with large crystals of black spinel, which are also 

 dull from partial disintegration, a change apparently induced from 

 the intermixture of serpentine. 



A more close attention to the mineral above mentioned, both 

 as relates to its mineralogical and chemical properties, than I have 

 heretofore been able to bestow upon it, has convinced me that it 

 is fully entitled to constitute a new species, which I designate 

 Warwickite^ from its original locality. 



Mineralogical Descriptio7t. 



Primary form. Oblique rhombic prism. M on M = 93° to 94*^. 



Secondary form. The primary having its obtuse lateral edges 

 truncated, and its acute ones, beveled. The summits rounded. 



Cleavage parallel with the longer diagonal perfect. The cleav- 

 age planes thus obtained are finely striated vertically, and exhibit 

 very distinct, oblique cross cleavages. Fracture uneven. 



Lustre eminently metallic-pearly, of a copper-red color on the 

 perfect cleavage-faces ; in other directions, only vitreous in mode- 

 rate degrees. Color dark hair-brown to iron-gray. Opalce, except 

 in very thin fragments, when it is translucent and transmits a 

 reddish-brown light. Streak dark chocolate-brown. Decompo- 

 sing crystals are nearly iron-black with a faint tinge of purple. 



Brittle. Hardness = 5. 5 . . . 6.0. Sp. gr. 3.29. 



Chemical Description. 



When heated on charcoal before the blowpipe, it does not fuse, 

 but simply assumes a lighter shade of color. With borax, it dis- 

 solves with effervescence, affording while hot a yellow semi-opake 

 glass, which on cooling changes to a pale green and becomes 

 clear. It renders carbonate of soda opake, at the same time im- 

 parting to it a dull yellow tinge. In microcosmic salt, it melts 

 with effervescence, the globule being blood-red while hot, from 

 which it passes through orange-yellow as it cools, and finally be- 

 comes reddish-gray and opake. On being pulverized and heated 

 in a glass tube, it emitted moisture and hydro-fluoric acid. The 

 corrosion of the tube became still more distinct on the addition of 

 a few drops of sulphuric acid. 



