Sf'HALLER.] 



Minerals from Leon a Heights. 



207 



Calc. for formula. 



FeO (16.15) 17.08 



CuO 10.07 0.45 



S0 3 28.84 28.53 



H 2 (44.94) 44.94 



1(10.00 100.00 



Still a third specimen of pisanite shows a variation from 

 either of the two specimens described. The most noticeable 

 difference is the presence of about three per cent, of magnesia. 

 The material is somewhat impure and not in good crystals. In 

 the last column, below, is the calculated percentage for the 

 formula 3CuO.FeO.Mg0.5SO:i.r)H 2 + 30H 2 O. The analysis 

 gave : 





Analysis. 



Iusol. deducted. 



Ratio. 



Calculated 



CuO 



16.40 



17.95 



3.09 



i— 1 



FeO 



4.99 



5.46 



.99 



5.21 



MgO 



2.58 



2.82 



.99 



2.92 



S0 3 



26.72 



29.25 



5.00 



28.97 



H 2 (110°) 



31.28 



34.25 



26.00 



39.10 



H.O (above 110° 



) 10.01 



10.96 



8.32 



6.52 



Insol. 



8.67 











100.65 



100.69 





100.00 



Though the fractional water determination is not very good, 

 it would seem as if the formula of this mineral might be written 



/g>R 



OS / X + 6H 2 , where R = (Cu, Fe , Mg ) in the ratio of 3 : 1 : 1 . 



\o>^- 



If we consider the magnesia as replacing part of the iron, the 

 formula becomes 3Cu0.2Fe0.5S0 3 +35H 2 0, which is not far 

 from pisanite, taken two and a half times, 2ACu0.2J Fe0.5SOs+ 

 35HoO. 



The mineral, described and named salvadorite by W. Herz,* 

 is of especial interest as differing somewhat from normal pisanite. 

 It is probably a variety of pisanite, in which the copper predom- 

 inates, approximating the formula 2CuO.Fe0.3S03+21H20. 



BOOTH IT E . 



General Description . — One of the secondary minerals occurring 

 in the Alma mine proves on investigation to be a new copper 



Zeitschr. Kryst. 1896, 2G, 16. 



