W. T, Schaller — California Minerals. 193 



Ratio. 



CuO -.. 26-13 1-00 



FeO _.. -81 -03 



MgO '64 -05 



SO, .- 27-25 1'04 



H 2 O(110°) 36-76 I , * 6 * 22 i'7.06 



H;O(ab.ll0°) ----- 4-91P 167 -84J- 706 



Insol 3-96 



100-46 

 Formula, CnS0 4 .H 2 + 6H 2 0. 



A careful determination of the specific gravity of the mineral 

 gave (21° C.) 1*944. This being much lower than the value 

 obtained (2*1) on the boothite from Leona Heights, a redeter- 

 mination of the latter was made on purer material collected 

 since the publication of the first results.* This gave, as an 

 average value, the figure (22° C.) 1*935. The average of these 

 two determinations, or 1*94, is probably very near the true value 

 for the specific gravity of boothite. 



PlSANTTE. 



A small specimen of massive pisanite from Gonzales, Monterey 

 Co., California, was analyzed some time ago and the results 

 are here presented. The quantity of material available for 

 analysis was very small and the determinations do not claim 

 any great accuracy. About 6 per cent of insoluble matter has 

 been deducted and the results recalculated to 100 per cent. 



Eatio. 



CuO ._ 7-56 *27 ) ftQ 



FeO 15*85 *72 y 



S0 3 _-. 30*74 1*08 



H a O 45-85 7-18 



100*00 



The analysis approximates to the formula Cu0.2Fe0.3S0 3 . 

 21H 2 0. 



In the following table, all available analyses of pisanite are 

 tabulated, and one can readily see that there is no definite ratio 

 between the copper and iron. The formula is then written 

 (Cu,Fe)S0 4 .7H 2 0, pisanite being an isomorphous mixture of 

 melanterite and boothite. AH the analyses are calculated to 

 100 per cent.f 



* Minerals from Leona Heights, Alamada Co., California, by W. T. Schaller, 

 Bull. Dept. Geol. Univ. of Cal., vol. iii, No. 7. 



f Anal. No. 1, theoretical comp. of melanterite, FeS0 4 .7H 2 0; No. 2, Schal- 

 ler, anal, quoted above ; No. 3, Schaller, Bull. Dept. Geol. Univ. of Cal., vol. iii, 

 No. 7; No. 4, Hintz, Zeit. Krys. ii, 309; No. 5, Hillebrand, Bull. U.S.G.S., 

 No. 220, p. 105 ; No. 6, see No. 3 ; No. 7, Pisani, Comptes Rendus, 1859, xlviii, 

 807 ; No. 8, see No. 3 : Nos. 9 and 10, Herz, Zeit. Krys. xxvi, 16 ; No. 11, 

 theoretical comp. of boothite, CuS0 4 .7H 2 0. 



