24 W. P. Headden — Kehoeite, a new Phosphate. 



R =Zri£-fCa 1 . The small amount of S0 3 present and the 



deportment of the material toward concentrated hydric acetate 

 indicate the absence of any significant quantity of basic sul- 

 phate or hydrated oxide of zinc. The analyses show an excess 

 of basic oxides over the quantity required by the P 2 5 present 

 in order to form neutral salts, and the fact that igniting the 

 material rendered a part of it insoluble may be interpreted in 

 the same sense, especially as the insoluble portion is quite free 

 from phosphoric acid and consists largely of alumina. On the 

 other hand the presence of zinc and phosphoric acid in the 

 hydric acetate solution is suggestive of the presence of a zinc- 

 ous phosphate. 



As a control on the water-determination, a portion of the 

 unwashed mineral which had been kept for upwards of three 

 years in a stoppered but unsealed bottle, and then exposed to 

 the atmosphere of a warm room for three days, was ignited 

 and showed a loss of 3148 per cent. I could not detect any 

 C0 2 in the mineral. 



The formula suggested, when R=Zn, requires : P 2 5 27*25, 

 A1 2 3 26-10 . ZnO 15*67 and H 2 31*09. 



The relationship of this mineral is not evident. If, how- 

 ever, the analysis made by Hermann on material from Rich- 

 mond, Mass., and given on p. 178, Dana's System of Min., 5th 

 ed., is correct, then there is an aluminic phosphate having the 

 formula Al 2 P 2 8 -f 9H 2 and the material presented in this 

 note may be a molecular combination of the following char- 

 acter : 2(Al 2 P 2 8 +9H 2 0)+2Al 2 (OH) 6 +(Zn 3 P 2 8 + 3H 2 0). 



I propose Kehoeite as the name of this mineral, after Mr. 

 Henry Kehoe, to whom I am indebted for the material and 

 who was the first to oBserve its occurrence. 



Note on Jarosite. — This mineral is found as a coating in 

 and sometimes partly filling larger cavities in the auriferous 

 quartzite which is the chief ore obtained in the Buxton mine, 

 Lawrence Co., S. D. It also occurs in the smaller cavities of 

 the rock and in distinct crystals associated with small quartz 

 crystals which cover old fracture-planes in the rock. The 

 jarosite where it is free from limonite has a golden yellow color 

 and the mass is composed of scales which under the micro- 

 scope appear as six-sided plates. The largest crystals observed 

 were about 2 mm in breadth and have a light brown color ; their 

 form could be recognized with the aid of a good magnifier as 

 a combination of a rhombohedron and the basal plane. 



The purest material that I could select gave : 





