ZIRCONIA. 337 



Zirconia . . . 75 

 Silica ... 25 



Oxide of iron , . 0'5 



100-5 



If we suppose the iron foreign, and the mineral a 

 simple silicate, then the atomic weight of zirconia 

 would be 6, which, from experiments immediately 

 to be mentioned, I believe to be its true weight. 



There is another mineral containing zirconia, C 

 which was discovered by Sir Charles Giesecke, <Ste. ei 

 at Kangerdluarsuk in Greenland ; and to which 

 Professor Stromeyer, to whom we are indebted 

 for a knowledge of its composition, gave the 

 name of eudialite. It was found by Giesecke 

 on the west coast of Greenland, in the same bed 

 that contains the sodalite, and intimately mixed 

 with that mineral and with hornblende. It is 

 sometimes amorphous, and sometimes crystallized 

 in rhomboidal octahedrons, with their edges 

 truncated : it has a rose red, or rather a hyacinth 

 red colour : it is hard enough to scratch glass, 

 but is easily scratched by pyrope : it is easily re- 

 duced to powder, and the powder has a red 

 colour : the specific gravity is 2*90355, according 

 to Stromeyer : it is, therefore, considerably light- 

 er than the pyrope, to which it bears a certain 

 degree of resemblance. The specimen of this 

 mineral in my possession, and for which I am 

 indebted to the liberality of Sir Charles Giesecke, 



VOL. I. Y 



