204: Genth and Penfield — Contributions to Mineralogy. 



The loss by ignition is almost the same, as the amount of 

 S0 3 found in the second portiou, which seems to indicate that 

 the mineral under consideration contains no water, but only 

 sulphuric acid. The ratios of S0 3 : Fe„0 3 would be 



in the first portion, 0-336 : 0-344 or 1 : 1 

 in the second portion, 0-339 : 0*353 or 1 : 1 



so that the composition of the iron sulphate would be 



Fe 2 3 . S0 3 or Fe 2 S0 6 



What the other IT or 18 per cent are could not be ascer- 

 tained on account of the minute quantity of material. We 

 hope to be able to secure more of this mineral from the 

 Mimbres Mine, and also a sufficient quantity of utahite for a 

 new analysis. At any rate, it is thought that the above data 

 should be placed on record. 



5. Picropharmacolite, from Poplin, Mo. 



Mr. Edward D. Drown of this city presented me with a speci- 

 men which he had received as coming from Joplin, Mo. It 

 occurs in incrustations upon a coarse-grained, cleavable dolomite 

 which are from 2 to 15 mm thick and are composed of radiating 

 silky fibers, forming botryoidal, globular or mammillary masses. 

 The appearance of this incrustation and the results of the 

 analyses indicate the probability of its being a mixture of sev- 

 eral varieties of the same mineral, — which I had no means to 

 separate. 



That which is most uniform forms botryoidal crusts from 2 

 to 3 mm in thickness made up of radiating silky fibers in globu- 

 lar aggregations: the analysis I, a and b. In the cavities of 

 the incrustation there are often very delicate silky fibers 2 to 

 gmm i n lengt]^ or the globules are covered with very minute 

 acicular crystals. The analyses of botryoidal incrustations, 

 more or less mixed with acicular crystallizations, are given in 

 II, a, b, c. In analyses III, the radiating silky groups from 

 another portion of the specimen are given, after the powder 

 had been placed over H 2 S0 4 for about one month. The mate- 

 rial for each batch was carefully powdered, and thus uniform- 

 ity was secured. 



I. Specific gravity taken in alcohol was 2-583. The analyses 

 gavi 







a. 



b. 



Mean. 



Mol. 



Ratio. 



Insoluble 





0-17 



0-16 









Loss at 100° 



C. 



11-60 











Loss at ignition 



. 11-44 



23-17 



23-11 



1-284 



6-2 



CaO - 





22-40 



22-44 



22-42 



404 



1-95 



MgO 





660 



6-68 



6-64 



0-164 



0-79 



MnOo 





0-21 



0-31 









Aso0 5 





47-48 



47-73 



47-60 



0-207 



1-0 













99-90 



100-49 



99-77 







