108 W. P. Headden — Stannite and some of its 



It is true that we can give an interpretation to the ratios 

 obtained, but a simple and necessary relation between them is 

 not evident. Still if we assume the iron present as xantho- 

 siderite and the copper as cupric hydrate we obtain the follow- 

 ing : Fe 2 3 2H 2 0, 3Cu(OH) 2 , 5Sn(OH) 4 , 3Sn0 2 . This would 

 demand but two more atoms of oxygen than we have really 

 found and this slight violence to the ratios found may be 

 justifiable on the ground that these ratios are only approxi- 

 mate. 



The identification of a new mineral, cuprocassiterite, has 

 recently been announced by Mr. Titus Ulke.* The material 

 which served for this identification was also from the Etta 

 Mine and according to his description from the same (?) point 

 in the mine, as no work has been done at this locality for seve- 

 ral years, no new openings have been made. Mr. Ulke does 

 not give the detailed results of his analysis but states " Upon 

 analysis 60 per cent Sn, 12 per cent Cu, and 8 per cent H 2 

 were found with traces of iron and silica." This when calcu- 

 lated into oxides in which form ttiese constituents evidently 

 existed in the material gives : 











At. 



equiv. 



SnO a 



76-27 



Sn 



60-00 



5-08 



5 



CuO 



15-04 



Cu 



12-00 



1-94 



2 



H„0 



800 



H 



•888 



8-88 



9 







O 



26-43 



16-52 



16 



99-31 



Mr. Ulke proposes 4Sn0 2 + Cu 2 Sn(OH) t . as the formula cor- 

 responding to this analysis. He notices the presence of iron 

 and silica but as the calculated analysis falls less than seven- 

 tenths of one per cent short of one hundred there could have 

 been no considerable quantity of either of these present. This 

 must be an accident, for as 1 have stated before, the probabili- 

 ties are strongly in favor of the material serving for the re- 

 spective analyses being from the same spot, again there can be 

 no doubt but that this material is an alteration product derived 

 from stannite and it is somewhat remarkable that the iron 

 should be so completely removed while the copper and so 

 much of the tin remains in the form of hydrate. The vary- 

 ing composition of this material is not only indicated by the 

 difference in the quantity of iron present but also by the ratios 

 of the anhydrous to the hydrous oxides. Mr. Ulkes gives 



4 : 2, i. e. 4Sn0 2 : - c fk-crv while my analysis gives 3 : 9, i. e. 



3Sn0 2 :Fe 2 3 2H 2 + 3Cu(OH) 2 4-5Sn(OEH 4 in which the cop- 

 per is considered as cupric instead of cupruus hydrate. 



* Proceeding- American Institute of Mining- Engineers, meeting of Feb., 1892. 



