34 



MEMOIR ON EMERY. 



Localities. 



Village Green., 

 Village Green., 

 Village Green., 

 Village Green. 

 Unionville 



Unionville 



Buncombe County. 



w 

 o' 



5' 



r 



CD 





II 



3 









SO 



: £? 





32.31 



49.24 



10.66 



0.30 



2.21 



5 . 27 



31.06 



51 . 20 



9.24 



0.28 



2.97 



5.27 



31.26 



51.60 



10.15 



0.50 



1.22 



4.27 



30.18 



51.40 



10.87 



0.92 



2.77 



4.52 



29.99 



50.57 



11.31 



0.72 



2.47 



5.14 



32.15 



54.28 



11.36 



0.05 



notesti- 

 mated. 



0.50 



29.17 



48.40 



9.S7 



1.24 



6.15 



3.99 



=100 



=100 



=100 



=100.46 



=100.10 



HF 2.03 =100.80 



Craw. 

 Craw. 



Craw. 

 Craw. 



Hartshorne. 

 Silliman, Jr. 



My analyses were made in the ordinary way, only with 

 more carbonate of soda than is usually employed. The alka- 

 lies were separated either by means of hydrofluoric acid or by 

 carbonate of lime, which is preferable to the carbonate of baryta 

 for the decomposition Of the silicates. 



It is seen that potash and soda are present in small quan- 

 tities in all the specimens. The composition of this mineral is 

 remarkable for the large proportion of alumina present ; but 

 when we look at its origin it is not astonishing to find a silicate 

 of alumina with a small amount of silex. 



I regard emery lite as a mineral of elimination from emery, 

 the result of an effort by which the corundum in its formation 

 purifies itself. It is not remarkable that from the mass in 

 which the corundum crystallizes the silica, finding itself in 

 presence with an excess of bases, combines with as large a 

 quantity as its affinity admits of. In speaking of the formation 

 of emery I have already alluded to a nodule in my possession 

 that exemplifies this in a very exact manner. 



Notwithstanding the recent discovery of emerylite, there is 

 no other species of mica that can be considered so well estab- 

 lished as this mineral or so constant in its composition.. Up to 

 the present time this mineral has not been found except with 

 emery or corundum, which frequently contain it in the interior 

 of the mass as well as on the surface. Some emeries contain it 

 in such quantity that it has the aspect of gneiss, as I have 

 already said with reference to certain specimens from Nicaria. 



The most beautiful specimens of emerylite come from Naxos, 

 and as the blocks of emery from this island frequently contain 

 it there will be no difficulty in procuring specimens for cabinets. 

 It is often mixed with diaspore. 



