388 Prof. B. Silliman, Jr., on some American Minerals. 





structure and hardness equal to kyanite. Thomson also has an- 

 alyzed a mineral from Chester Co., in Pennsylvania, well known to 

 collectors, and has referred it to Bucholzite.* Being in possession 

 of authentic specimens of the Chester mineral, I have analyzed it 

 with the following result. Quantity taken 0*561 gramme. Found, 



Si 



Al 



Mg 



Mn 



1925=perct. 34-31 



Another sample. 



35*96 



3615 



0028 



trace 



a 



a 



a 



64-43 

 •52 



trace 



5568 



99-26 



This also will give us the same formula with kyanite. The 

 mineral being less pure than sillimanite, cannot be expected to 

 furnish results as accurate as the former analysis. Prof. Shepard 

 in his "System" expresses the opinion that bucholzite and silli- 

 manite were the same species. 



There is also found at Brandywine Springs, Delaware, a min- 

 eral which has been extensively circulated under the name of 

 both bucholzite and fibrolite. A specimen from this locality fur- 

 nished me the following results, viz.: Quantity taken 10675 



gramme 



Found 



Silica, 

 Alumina, 



•386 

 •679 



1-065 



perct. 36-159 

 " 63-525 



99-684 



This is evidently identical with kyanite. Minute traces of 

 iron and manganese, which are found in both the above, are re- 

 garded as of no importance in the result, being mere impurities. f 



Fibrolite of Bournon. This mineral was first distinguished by 

 Count Bournon, who detected it among the associated minerals 

 of corundum from India and from China. The name has refer- 

 ence to its fibrous character. It was analyzed by Chevenix, who 

 found 



* Erdmann appears also to have made his analysis on the mineral from the same 

 locality. 



f It may be objected to the conclusion that bucholzite is identical with kyanite 

 that I have not analyzed a specimen of the original mineral. This I should have 

 done could I have procured one in season for my present purpose. The Chester 

 mineral hen- analyzed was received by Baron Lederer from Dr. Nuttall, and so far 

 as I can learn, no one questions that the mineral from that locality corresponds en- 

 tirely with the bucholzite of Brandes. I am convinced that those chemists who 

 have obtained so high a percentage of silica in their analyses of disthene minerals, 

 have not tak m the precaution to employ the aid of caustic potassa, added to to* 

 assay during fusion, as recommended by Berzelius; and that if they had re-analyzed 

 theii iliea they would invariably in cases where the amount exceeded 38 per cent- 

 have found init a portion of alumina. 



