198 Lindgren, Hamilton, Palache — Melanovanadite 



or approximately 3:2: 2. The formula would, therefore, 

 be 



2 CaO.3 V 2 5 .2 V,0 4 



The calculated composition of this would be 



V 2 5 55.16 



V 2 4 33.51 



CaO : 11.30 



100.00 



Before the blowpipe the mineral fuses very easily to a 

 brown liquid but gives no flame reaction for calcium. 

 It gives strong bead reaction for vanadium. It is 

 easily soluble in dilute HN0 3 , HC1, and H 2 S0 4 , with 

 apple-green color. In concentrated HN0 3 it dissolves 

 with evolution of red fumes to a dark brown solution. 

 Upon evaporation it gives a red or brown residue. It is 

 also easily decomposed by KOH with brownish color. 



In May, 1921, a small sample of the mineral was sent to 

 Dr. W. T. Schaller of "Washington. The material had 

 then for some time been exposed to a warm damp atmos- 

 phere. Dr. Schaller stated in a letter that the mineral 

 appeared to contain much water. In view of this, the 

 following re-examination was undertaken. A dry tube 

 test showed at once that this was now true, an abundance 

 of water being given off. The larger part was driven off 

 upon drying at 105°, but equally large amounts were lost 

 in desiccator above sulphuric acid. A sample in desiccator 

 lost 10.26% H 2 in twelve days ; the weight was taken for 

 six more days, but remained constant. The dried mate- 

 rial took up water rapidly after being removed from the 

 desiccator, even while it was being weighed. 



The most representative results showed a loss of 10.7% 

 H 2 upon drying at 105° C. About 5.9% was held above 

 105°, making a total water content of 16.6. The exact 

 point at which this last water was given off was not deter- 

 mined on account of the very low fusion point of the 

 mineral. 



A sample carefully cleaned and finely ground and dried 

 for two days at 105° C. gave the following figures: 



