BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 19, pp. 93-98 June i, i908 



OCCUEEENCE OP PEOUSTITE AND AEGENTITE AT THE 

 CALIFOENIA MINE, NEAE MONTEZUMA, COLOEADO^ 



BY FRANK E. VAN HOKN 



{Read before the Society December 30, 1907) 



CONTENTS 



Page 



Introduction and brief description of mine 93 



Principal ore of mine and assays of same 94 



Occurrence of the pi'oustite 95 



Occurrence of the argentite 96 



Paragenesis of the ores 97 



Conclusion 98 



Introduction and brief Description of Mine 



During the fall of 1903 the officers of the Mine Developing Company 

 of Cleveland presented the geological department of Case School of Ap- 

 plied Science with several vein sections and specimens of high grade silver 

 ore from their California mine in Colorado. The writer has obtained 

 most of his information concerning the mine from the officials of the 

 company, whom he wishes to thanlv for both information and specimens. 



The California mine, formerly known as the Bell property, is situated 

 on Glacier mountain, about 3 miles from Montezuma, Summit coimty, 

 Colorado. The ore occurs in a fissure vein having a dip of approximately 

 30 degrees to the northwest and a strike which varies from 30 to 50 de- 

 grees northeast and southwest. The country rock is a coarsely foliated 

 granitic gneiss in which the biotite has altered to chlorite minerals near 

 the vein; this alteration was probably due to normal weathering, and not 

 to the action of the solutions which deposited the vein matter, as no cases 

 of impregnation of ore minerals were noticed outside the vein wall in any 



1 Manuscript received by the Secretary of the Society December 30, 1007 



X — Bull. Geol. See. Am., Vol. 19, 1907 (93) 



