8. L. Penfield — Mineralogical Notes. 897 



1. Zunyite from Med Mountain, Ouray Co., Colorado. 



In 1884 Mr. W. F. Hillebrand* described a new mineral 

 zunyite from the Zuni Mine, near Silverton, San Juan Co., 

 Colorado. It is interesting to know that a second locality has 

 been found for this rare mineral, at the Charter Oak mine, 

 situated on the hill, only a short distance east of the village of 

 Red Mountain. This is about five miles north of the original 

 locality and on the same mountain chain. 



When visiting the mine, my attention was called by the 

 superintendent, Mr. C. A. Taylor, to a very hard rock which 

 had been taken from the shaft. This is fine grained, of a 

 grayish white color, and with the lens one can readily detect 

 the little bright tetrahedrons of zunyite, about l mm in diam- 

 eter, sometimes scattered sparsely, sometimes abundantly, 

 through it. An examination of thin sections with the micro- 

 scope shows that the rock is a porphyrite, very much altered 

 by steam and fumerole action, so that only remnants of the 

 original minerals are left. The zunyite crystals are fresh and 

 clear and show no double refraction with polarized light. 



The pulverized rock was almost an ideal one to treat with 

 the Thoulet solution. An approximate separation of the 

 zunyite crystals was first made. This product was then further 

 purified by digesting with dilute hydrochloric and hydrofluoric 

 acids, which have no appreciable solvent action on the zunyite, 

 and then again separated with the heavy solution, giving a 

 very pure product. Most of the mineral had a specific gravity 

 between 2*904 and 2 - 8T6 and only this portion was used for 

 the chemical analysis, the results of which are given below, 

 together with the original analysis of Mr. Hillebrand. 





1. 



II. 



Average. 



Ratio. 





Hillebrand 



Si0 2 



2411 



24-10 



24-11 



•402 



3-00 



24-33 



Alo0 3 





57-20 



57-20 



•561 



448 



57-88 



Fe. 2 3 





•61 



•61 







•20 



CI 



2-61 



262 



2-62 



•074 ) 





2-91 



F 



592 



5-70 



11-18 



•64 



5-81 



11-12H 



•64 



•306 [ 1-616 

 -9=1-236 ) 



12 06 



5-61 



H,0 



11-06 



1089 



P 2 6 





•60 



CaO 





11 



•11 







KoO -10 



NaoO 





•48 



•48 







•24 





102-70 



10276 





equivalent 



to CI and F 



303 







3-C2 



99-67 99 74 



The analysis was made on air-dry material which lost only 

 06 per cent by drying for one hour at 100° C. and an addi- 

 tional 0*15 per cent by heating for one hour at 300° C. The 

 water is therefore regarded as formed from hydroxyl, with 



*Proc. Col. Soc, i, p. 124, 1884. Also Bulletin No. 20, U. S. Geological 

 Survey, p. 100. 



