Analysis of Warwickite. 85 



Art. IX. — Analysis of Warwickite ; by Charles Upham Shep- 

 ARD, M. D., Professor of Chemistry in the Medical College of 

 the State of South Carolina. 



In proposing the Warwickite as a new mineral species in a late 

 number of this Journal, (Vol. xxxiv, p. 313,) I remarked that I 

 should avail myself of a distinct crystal of the substance, belong- 

 ing to my mineralogical collection here, for obtaining a more cor- 

 rect knowledge of its chemical constitution. The results of the 

 proposed inquiry are embraced in the following notice. 



The crystal referred to was nearly two inches long, by one 

 third of an inch in diameter, and imbedded in white magnesian 

 limestone. It was presented to me by Dr. Horton, and is ticket- 

 ed Amity, which town adjoins Warwick, where the mineral was 

 -first discovered. 



The specimen in hand affords but indistinctly the metallic re- 

 flections, so striking in the smaller crystals from Warwick. Its 

 diagonal cleavages also are less distinct. The color is grayish 

 brown, approaching to black. The crop-cleavage is very obvious, 

 and is oblique to the axis. Lustre, imperfectly metallic, in which 

 respect it resembles columbite and some varieties of rutile. Sp. 

 gr. = 3.0...3.14. Hardness = 6.0. 



Its powder is of a chocolate-brown color, which during ignition 

 changes to purplish black ; and the mineral loses during the pro- 

 cess 8 p. c. in weight — the particles afterwards cohering together 

 in a a porous mass. 



1. On being treated in powder with sulphuric acid in a platina . 

 crucible, it slowly swells up and emits bubbles of hydrofluoric acid 

 gas. The application of heat causes a brisk eff"ervescence ; and 

 on holding a plate of glass over the capsule, it is distinctly cor- 

 roded by the acid vapor. A little water was added and the diges- 

 tion maintained for half an hour, when the whole of the powder 

 had suflered decomposition, having passed through various shades 

 of purple and gray to a pale, yellowish white. On adding more 

 water and boiling, the whole was taken into solution. 



2. A portion of the clear sulphuric solution 1, was farther dilu- 

 ted and boiled, whereupon it threw down titanic acid in large 

 quantity. 



