BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 15, PP. 283-288, PLS. 12-13 JUNE 25, 1904 



MOLYBDENITE AT CROWN POINT, WASHINGTON 



BY A. R. CROOK 



(Presented before the Society December 30, 1903) 



CONTENTS 



Page 



Introduction 283 



Literature 284 



Occurrence of molybdenite at other localities 284 



Petrographical relationships , 284 



Accompanying minerals 285 



Form of deposits. 285 



Location of Crown Point mine 285 



Form of the deposit. ! 286 



Inclosing rock 286 



A naly ses 287 



Character of the molybdenite 287 



Paragenesis 287 



Associated minerals 287 



Source , 287 



Introduction 



The occurrence of molybdenite (MoS 2 ) at Crown Point, Chelan county, 

 Washington, is one of the most interesting in the United States for sev- 

 eral reasons : First, because practically the entire commercial supply of 

 the mineral in the United States for 1902 was mined at this locality. 

 The amount is given by Dr J. H. Pratt as about twelve tons of ore.* 

 Second, because the locality presents an interesting illustration of the 

 geologic relations of the substance ; and third, because so large a quan- 

 tity of this comparatively rare mineral naturally furnishes excellent 

 specimens representing the mineralogical character of molybdenite. 



Commercially molybdenite is important as the chief source of molyb- 

 denum. This element has long been used as a pigment for coloring silk, 

 leather, and porcelain. The color which it furnishes is a brilliant, uni- 

 form, and permanent blue, and is especially prized for glazed ware. 



* Mineral Resources of the United States, 1902, p. 7. 

 XXXVII— Bull. Geol. Soc. Am., Vol. 15, 1903 (283) 



