110 



RE-EXAMINATION OF AMERICAN MINERALS. 



Minor, and the suggestion that it might be found with the 

 corundum of other localities. 



The analyses which were immediately made of this mineral 

 by different chemists, on specimens coming from various parts 

 of the world, showed a uniformity of composition most re- 

 markable in a micaceous mineral, and so it was considered by 

 a committee of the Academy of Sciences at Paris, who reported 

 on this subject .* This fact is most clearly seen by reference to 

 the following table of analyses made in 1850 : 



Localities. 



Gum uch-dagh 



Island of Nicaria... 

 Island of Nicaria... 

 Island of Naxos.... 

 Island of Naxos.... 

 Island of Naxos ... 



Gumuch-dagh 



Gumuch-dagh 



Siberia 



Village Green, Pa- 

 Village Green, Pa- 

 Village Green, Pa- 

 Village Green, Pa- 

 Buncombe Co., N.C 



Unionville, Pa 



Unionville, Pa 



Si 



30.22 

 29.87 

 30.02 

 28.90 

 30.10 

 30.90 

 31.93 

 28.50 

 32.31 

 31.06 

 31.26 

 30.18 

 29.17 

 29.99 

 32.15 



'A\ 



50.88 

 ■49.67 

 48.48 

 49.52 

 48.53 

 50.08 

 48.21 

 48.80 

 51.02 

 49.24 

 51.20 

 51.60 

 51.40 

 48.40 

 50.57 

 54.28 



Ca 



13.56 

 11.57 

 10.84 

 10.82 

 11.92 

 10.80 



9.53 



9.41 

 12.05 

 10.66 



9.24 

 10.15 

 10.87 



9.87 

 11.31 

 11.36 



1.78 

 1.33 

 1.63 

 1.65 

 .87 

 not est. 

 2.81 

 1.50 

 1.78 



Mg 



.50 

 trace 

 trace 



.48 

 not est. 



.30 



.28 

 .50 

 .72 

 1.24 

 .62 

 .05 



K&Na H 



1.50 

 2.31 



2.86 



1.25 



not est. 



2.31 



not est. 

 2.21 

 2.97 

 1.22 

 2.77 

 6.15 

 2.47 



not est. 



3.41 

 5.12 

 4.32 

 5.55 

 5.08 

 4.52 

 4.61 

 3.62 

 5.04 



Mn 



H F 2.03 



J. L. Smith. 



W. J. Craw. 



Silliman, jr. 

 W. J. Craw. 

 Hflrtshome 



It was suspected by us, at the time the species was made, 

 that it might prove identical with margarite; but not having 

 the latter mineral at hand, we had to proceed on the known 

 analyses of it, which we here give. The first is by Dumeril ; 

 the second by the Gottingen Laboratory, on the authority 

 of Hausmann. 





Si 



XI 



¥e 



Ca 



Na 



H 



1. 



37.00 



40 50 



4.50 



8.96 



1.24 



■1.00=93.20 



2. 



33.50 



58.00 



Fe 

 0.42 



7.50 



Mn 

 0.03 



Mg 

 0.05=99.50 



These analyses differing so materially from those of emery- 

 lite, fully justified the formation of the species. 



As soon as margarite could be procured it was subjected to 

 analysis, and the inaccuracy of former analyses proved; but 

 we had not at that time sufficient of the mineral to complete 

 the investigation as desired. In the mean time Hermannf re- 

 analyzed it, found a different composition from any previous 



* Comptes Bendus de l'Academie des Sciences, Oct. 28, 1850. 

 f J. f. pr. Chem., liii, 1. 



