Melanterite and Chalcanthite Groups. 



233 



Hungary 1 is a nearly white chalky aggregate of very min- 

 ute fibers or plates, probably monoclinic with Z = b. 



a = 1.57 ± 0.01. y = 1.62 ± 0.01. 



The optical properties of the hydrous sulphates of 

 cobalt and manganese are tabulated in Table IV. 



Table IV. Optical properties of the hydrous sulphates of cooalt and man- 

 ganese. 





MnS0 4 



1C0SO4 



2CoS0 4 



MnS0 4 



MnS0 4 



CoS0 4 



CoS0 4 



CoS0 4 





1H 2 



1H 2 



1H 2 



4H 2 



5H 2 



5H 2 



6H 2 



7H 2 



System 



Monocl (?) 







Monocl (?) 



Tricl. 



Tricl. 



Uniax. 



Monocl. 



Habit 





Fibers 

 Crusts 



Crystals 



Tab. 









Tab. 



Opt. char. 



+ 



a 



+ 



— 



— 



— 



— 



— 



2V 



near 90 



a 



near 90 



mod. lge. 



rather 

 lge. 



med. 







near 90 



a 



1-562 



1-600 



1-603 



1-508 



1-495 



1-530 



1-460 



1-477 



P 



1-595 





1-639 



1-518 



1 -508 



1-548 



| 1-495 



1-483 



7 



1-632 



1-645 



1-683 



1-522 



1-514 



1-550 



1-489 



1 Formed when CoS0 4 solution is evaporated to dryness on a water bath. 



2 Formed in small amount when CoS0 4 .6H 2 is allowed to dehydrate in a 

 desiccator at room temperature. 



4 Unpublished manuscript by E. S. Larsen. 



