SohaltjKR.J 



Minerals from Leona Heights. 



calcium chloride tube, fractional water determinations being' 

 usually made. It was found, by experiment, that all of the 

 water of these sulphates was given off below 300° C. 



PYBITE. 



General Description . — The ore of the Alma Mine consists 

 chiefly of massive pyrite intermixed with some chalcopyrite and 

 usually carrying small values of gold and silver. Crystals of 

 pyrite occur scattered through the rock, which is rhyolite, often 

 largely decomposed to clay. The crystals described here, were 

 collected some years ago at the opening of the mine by Mr. Fritz 

 Bohmer, of Alameda, who kindly placed them at the disposal of 

 the writer. 



CrystallograpMc Characters, — On examination with the lens, 

 the crystals, ranging up to 3 mm. in diameter, and even occasion- 

 ally somewhat larger, were found to consist principally of the 

 pyritohedron 1 120 1 , with occasionally the cube and the octo- 

 hedron. The cube faces are invariably narrow and the octahedral 

 faces triangular in shape, the latter varying in size up to about 

 one-third the size of the pyritohedron !l20j. 



All of the larger crystals are more or less rounded and the 

 faces uneven and often dented, always giving a large number of 

 reflections. The ten forms below were definitely established and 

 a few more possibly are present, but on account of the lack of 

 sharpness of the signals, their identification is somewhat 

 uncertain. 



Letter. 



Symbol. 



Letter. 





Symbol. 





Gdt. 



Miller. 





Gdt 



Miller 



a 



0=o 



100 



O 



] 



111 



(I 



GO 



110 



CO 



1|- 



252 



8 



** 



340 



n 



12 



121 



e 



oo2 



120 



t 



24 



241 



It 



co 4 



140 



s 



23 



231 



The forms {100} , |li0|, |340| and {140j occur as narrow 

 and rounded faces. Of the other forms only §120| and Sill} 

 were well developed. The remainder were all small and the 

 complete number of faces belonging to each form was not always 

 present . 



