DR T. THOMSON'S Analysis of some Minerals. 475 



IX. Kittinite. 



This mineral was discovered some years ago by Dr TAYLOR, 

 in coarse granite veins in fine-grained granite at Killiney, Dub- 

 lin Bay. In the veins it is mixed with a good deal of spodu- 

 mene. It was analyzed at the time by Dr BARKER and Dr 

 TAYLOR, who found the constituents as follows : 



Silica, ...... 52.49 



Alumina, 24.30 



Potash, 5.00 



Protoxide of iron, . . 2.49 



Lime, , 0.50 



Oxide of manganese, . 0.75 



Water, 0.50 



90.53 



But I have reason to suspect, both from the description and from 

 the specimens which I saw some years ago in Dublin, that the spe- 

 cimens in the possession of these gentlemen were rather impure. 



Captain LEHUNT and Dr STOKES junior visited Killiney du- 

 ring the summer of 1828, and procured abundance of very good 

 specimens. Captain LEHUNT was so obliging as to present me 

 with a very pure crystallized specimen of a large size, and seem- 

 ingly quite pure. This, together with a good many other spe- 

 cimens already in my possession, puts it in my power to describe 

 Killinite with more precision than has yet been done. 



The usual colour is brownish-yellow ; though occasionally it 

 has a tint of green. I have seen specimens of a green colour, 

 but they are comparatively rare. When heated to redness, some 

 .specimens become snow-white, while others assume a reddish 



VOL. XI. PART II. 3 



