138 Notice of DaJiburite, a neio Minei^al Species. 



Mineralogical Description. 



Primary form. Oblique rhombic prism. 



Cleavage parallel with P indicated obscm-ely by fissm-es. 



Lustre vitreous, in a high degree. Color shades of honey yel- 

 low. Streak white ; transparent. (The decomposing variety is 

 nearly white, translucent and very fissile.) 



Hardness=7.5. Sp. Gr. =2.83. 



Chemical Description, 



When heated alone before the blow-pipe, it phosphoresces and 

 fuses slowly without intumescence into a white blebby, transpa- 

 rent glass. With borax, it melts with effervescence into a trans- 

 parent globule. When heated in a glass tube, it emits moisture. 

 In the condition of an impalpable powder, it is taken up by hy- 

 dro-chloric acid after long digestion. 



By the requisite trials, it was found to contain neither fluoric, 

 boric, nor phosphoric acid. By heating, it lost 8 p. c. in~weight. 

 By ignition with twice its weight of anhydrous carbonate of 

 soda, it fused into a white mass, which formed a colorless solu- 

 tion with dilute hydro-chloric acid. After the separation of the 

 silica, which weighed 56 p. c, the solution was precipitated -by 

 ammonia, and the precipitate treated with carbonate of ammonia 

 solution in large excess, which after frequent agitation and some 

 time standing was partially evaporated ; a pale yellow pellicle in- 

 vested the sides of the capsule, which after drying weighed 0.85 

 p. c. It was treated with hydro-chloric acid, and the solution 

 obtained aflbrded when tasted no impression of sweetness. Its 

 yellowish color and easy solubility after ignition in hydro-chloric 

 acid proved it not to be zirconia ; while the absence of sweetness 

 showed that it was not glucina. It seems most probable there- 

 fore, that it is yttria. 



The portion of the precipitate by ammonia not taken up by 

 the carbonate of ammonia, was treated with a solution of potassa. 

 It was instantly dissolved, and on being precipitated with hydro- 

 chlorate of ammonia, washed and ignited, it amounted to L7 p. c. 



The clear hydro-chloric solution from which the alumina and 

 yttria ? had been separated was precipitated by oxalate of ammo- 

 nia, and the precipitate was washed and ignited. The residuum 

 gave 28.33 p. c. of lime. 



