40 MEMOIR ON EMERY. 



This titaniferous iron corresponds in composition to the 

 Washingtonite of Prof. Shepard analyzed by M. Marignac, and 

 to the titaniferous iron of Arendal analyzed by M. Mosander. 

 Its sp. grav. is 4.78. 



There are still two or three minerals that I have found as- 

 sociated with emery, but their specific characters have not 

 been well established on account of the difficulty of obtaining 

 enough in a state of sufficient purity for analysis. 



The study of these accidental minerals in contact with 

 emery has led to several general conclusions which have been 

 mentioned under the description of the different species; and 

 now I risk little in saying that the hydrates of alumina, as 

 diaspore — as well as the silicates, as emerylite, chloritoid, and 

 tourmaline — and the minerals of iron, as magnetic, titaniferous 

 iron, etc., will be found almost every where with the emery and 

 corundum. 



My labors on this subject are thus terminated, and it is to 

 be hoped that the examination of the emery of Asia Minor has 

 served to elucidate the geology and mineralogy of this sub- 

 stance, until now but little known except in its uses. 



