284 A. R, CROOK MOLYBDENITE AT CROWN POINT, WASHINGTON 



Molybdenum finds a limited use in chemical laboratories for the detec- 

 tion of phosphoric acid and as a medicine for the cure (?) of dropsy.* 

 The chief demand for the element, however, is one which has arisen re- 

 cently in the manufacture of steel, a fraction of a per cent producing an 

 effect analogous to that obtained by the employment of wolfram and 

 nickel. The price paid for molybdenite ores varies to a surprising degree, 

 from $150 to $1,500. The variation is caused largely by the presence or 

 absence of chalcopyrite, a small amount of the substance having a very 

 deleterious effect. 



Literature 



Though the Chelan deposit has been known and worked for a number 

 of years (since 1897 or 1898), the literature in reference to it is meager. 

 In Hintze's comprehensive list of occurrences it is not mentioned. • The 

 only references which the writer has found are in the Washington Geo- 

 logical Survey report for 1901 f and the " Mineral Resources of the 

 United States " from 1899 to 1902. 



A short visit to the mine in 1902 enabled the writer to collect speci- 

 mens of the mineral, gangue, and country rock, and to take photographs 

 of the lode. 



Occurrence of Molybdenite at other Localities 

 petrographical relationships 



At fifty or more localities in different parts of the world where molyb- 

 denite is reported, it occurs in a great variety of rocks and associated 

 with many different kinds of minerals. A survey of these occurrences 

 shows that it is found in practically all of the main groups of rocks, as 

 the following list will indicate.* It is found in 



1. Conglomerate (Switzerland). 



2. Granular limestone (Hessen, Ungarn). 



3. Contact of marble with pyroxenite (California). 



4. Serpentine (Tirol). 



5. Garnetite (Hessen). 



6. Amphibolite schist (Finland). 



7. Chlorite schist (Karnten, Sweden, Finland). 



8. Talc schist (Finland). 



9. Mica schist (Switzerland, Sweden). 



10. Gneiss (Baden, Mahren, France, Norway, Connecticut). 



11. Basalt (Sardinia). 



12. Pyroxenite (Canada). 



* Fuchs et Delauney : T raite des Gites Mineraux et Metal life res, 1893, ii, p. 175. 

 D. C Davies : Earthy and other Minerals, and Mining, 1892, p. 324. 

 t Washington Geol. Survey Annual Report, vol. i, pp. 92-93. 



