1885.] -^11 [Koenig. 



Note on Cosalite, Alaskaite and Beegerite. By Oeorge A. Koenig. 

 (Read before the American Philosophiaal Society, January 16, 1SS5.) 



The discovery of another rich vein of Bismuth silver ore in Ouray Co., 

 Colorado, last spring, has developed new interest in the sulphobismuthite 

 minerals. The new discovery is called "Gladiator," and is situated, 

 according to Mr. Stockder, my correspondent, at the mouth of Pough- 

 keepsie gulch into the Uncompaghre valley. The "Alaska" is situated 

 at the head of this gulch, some six or eight miles above the Gladiator. 



My esteemed friend and colleague, Prof. F. A. Genth, examined some 

 specimens of the new find, whilst others awaited my return from Europe. 



In connection with this investigation. Dr. Genth also analyzed material 

 from a specimen, which I had given him as "Alaskaite" from the Alaska 

 mine. The results of his analysis did not agree with the composition of 

 alaskaite, as found by me, but rather with cosalite. To make doubly 

 sure, he kindly asked me to repeat the analysis with well selected mate- 

 rial from the same specimen. I did so with the following result : 



98.69 

 Particles of chalcopyrite could not be excluded in picking. It we 

 deduct the iron, with a corresponding quantity of copper and sulphur as 

 chalcopyrite, we have 



or 2 RS + Bij S3 = Cosalite. 



Although I had used the same methods in the analysis of alaskaite, I 

 felt induced to reexamine my type specimens of that species. Upon 

 closer examination the difference in color between this cosalite and the 

 alaskaite becomes unmistakable. Still I might have been mistaken. The 

 material was picked with much care, more than in my first examination, 

 as will be seen by comparison of the results. It was scarce in conse- 



