448 Koenig — Mohaiokite, Stibio-domeykite, Domeylcite, etc. 



like razor-steel. Although very tough, it does not dent like 

 Whitneyite. The nodule was covered with Whitneyite and 

 this mineral shows on Dr. Hubbard's specimen like a thin 

 fringe around the algodonite. I could break off some 5 grams 

 of faultless material. The specific gravity was found at 21° C. 

 = 8'383 (using 3*8418 grams). The analysis made with 0*5 

 gram. Of silver I could find no trace. The analysis gave 



Cu 83-12 forCu°As 



(Fe, Ni, Co) 0-08 Cu... 83-5 



As 16-08 As 16-5 



99-88 



Calculated from these figures, the specific gravity is 8-406. 

 This gives a minus difference of 0-023 from my experimental 

 value of 8-383. 



Michigan College of Mines, June, 1900. 



