Palache and Warren — Krohnkite, N'atrochalcite. 347 



The water is given off gradually on continued heating above 

 150°. The mineral decomposes and gives off S0 3 between 

 350 = and incipient redness. Before the blowpipe it decrepi- 

 tates and fuses very easily (about 1) to a black bead. G-ives 

 off acid water in closed tube, fusing to a dark enamel. It is 

 very slowly dissolved by water and easily by acids. 



the analysis which follows was made on less than one gram 

 of material and is not wholly satisfactory to Dr. Warren, the 

 analyst ; lack of available substance, however, except at the 

 expense of one of the two remaining specimens, made it seem 

 well to publish it as it stands, subject to revision later should 

 more of the mineral be discovered. 





Per cent. 



Mol 



Eatio. 



Theory. 



CuO 



41-95 



•528 



4-0~0 



42-08 



]S r a,0 



S-44 



•136 



1-03 



8-24 



so; 



42-10 



•526 



4-00 



42-51 



H 2 



T'70 



•427 



3-23 



7-17 



Insoluble res. 



•70 







. 



CI from atacamite -05 



100-94 100-00 



Par agenesis. — Katrochalcite does not occur with krohnkite 

 in these specimens, but takes its place, bearing the same age 

 relations to atacamite and brochantite which occur sparingly 

 with it. As above mentioned, it is embedded in chalcanthite 

 in one specimen. 



Blbdite. — Blodite was identified by the following analysis. 

 It is a massive granular form of the mineral, white where 

 not stained blue by chalcanthite or pale green by finely divided 

 atacamite. It showed no trace of crystalline form. In one 

 specimen it was accompanied by halite and krohnkite. 



Composition, analysis by C. H. Warren : 





Per cent. 



Mol. 



Eatio. 



Theory 



MgO 



12-00 



•300 



1-00 



11-48 



Xa„0 



18-20 



•296 



0-98 



18-56 



SO" 3 



47-49 



•593 



1-98 



47-90 



H 2 



21-60 



1-20 



4-00 



21-56 



sol. -atacamite 











and quartz, 



•50 









99-70 . 100 00 



leading to the usual formula, MgS0 4 .Na 2 S0 4 -f 4H 2 0. 



