MEMOIR ON EMERY. 



33 



That which gave me the greatest specific gravity contained 

 some small specks of titaniferous iron visible to the eye. Its 

 optical properties have not been examined, for the want of a 

 transparent piece of sufficient size and thickness. This mineral 

 is not attacked by the acids. Heated before the blowpipe, it 

 emits a bright light, and melts with great difficulty on the 

 edges, which assume a blue color if touched with the nitrate 

 of cobalt and reheated. Heated in a tube, it furnishes water 

 frequently having an acid reaction due to fluoric acid. 



The composition of several specimens subjected to analysis 

 is as follows : 



Localities. 



Gumuch-dagh , 



Island of Nicaria 

 Island of Nicaria 

 Island of Naxos.., 

 Island of Naxos.. 

 Island of Naxos... 



Gumuch-dagh 



Gumuch-dagh 



Siberia 



CD 



a . 

 ? 



> 



| 

 5' 



3 



CD 



o 



o X 

 P © 



: o 



p 



ores 



C3 

 CD 



p' 



COo 



p j£, 



SO 

 CD 



3.41 



29.66 



50.88 



13.56 



1.78 



0.50 



1.50 



30.22 



49.67 



11.57 



1.33 



trace. 



2.31 



5.12 



29.87 



48.68 



10.84 



1.63 



trace. 



2.86 



4.32 



80.02 



49.52 



10.82 



1.65 



0.48 



1.25 



5.55 



28.90 



48.53 



11.92 



0.87 



not esti- 

 mated. 



not esti- 

 mated. 



5.08 



30.10 



50.08 



10.80 



not esti- 



it 



u 



4.52 



30.90 



48.21 



9.53 



2.81 



a 



(( 



4.61 



•31.93 



48.80 



9.41 



1.50 



" 



2.31 



3.62 



28.50 



51.02 



12.05 



1.78 



et 



not esti- 

 mated. 



5.04 



CD P 

 CO i-( 

 CD a 

 : CTQ 



trace. 



The oxide of iron may be regarded as an impurity which 

 exists between the plates of the mineral. The composition 

 of the emerylite is represented by 



ATOMS. AT. WEIGHT. PER CENT. OXYGEN RATIO. 



Lime 2 700.0 13.48 2 



Silica 3 1700.1 32.74 9 



Alumina 4 2566.5 49.44 12 



Water 2 225.0 4.34 2 



5191.6 



Formula: E 2 Si+23tl 2 Si+2H. 



As is seen, the specimens examined came from four distinct 

 localities, and were all taken under different circumstances ; 

 yet their analyses accord perfectly, and also agree with those 

 of the United States coming from Village Green and Union- 

 ville of Pennsylvania and Buncombe County, North Caro- 

 lina. 



